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1. Co-Designed Agile Feed Network for a Polarization Tunable 15 GHz Antenna All-Integrated on Silicon

Author

Corentin Le Lez, Rozenn Allanic, Denis Le Berre, Cedric Quendo, Francois Gallee, Aude Leuliet, Thomas Merlet, Rose-Marie Sauvage, Douglas Silva de Vasconcellos, Virginie Grimal, and Jerome Billoue

Subjects
Antennas, attenuators, polarization, PIN diode, reconfigurable, ScDDA, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

This article presents an all-integrated agile feeding network at 15 GHz enabling the polarization agility of a dual-fed patch antenna, allowing the switching between LHCP (Left Hand Circular Polarized), H-LP (Horizontal Linear Polarized) and V-LP (Vertical Linear Polarized) configurations. Semiconductor Distributed Doped Areas (ScDDAs) are used with an adequate size for the global function optimization and for integrated tunability on a High Resistivity Silicon (HR Si) substrate as variable shunt resistors in the attenuators. Each component of the system has been separately analyzed in small and large signal setups to highlight the relevance of the ScDDAs in this use case. The antenna and its reconfigurable feeding network are designed as a whole in a single process flow. The device allows for an analog control and high polarization contrast interpolating between H-LP, V-LP and LHCP polarizations. The high integrability, low bias voltage, manufacturing simplicity and tuning range of this device without sacrificing the antenna frequency is matching the needs of compacity, agility and robustness of next generation communication and RADAR systems.

Published
2024
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2. Generative Adversarial Networks for SAR Automatic Target Recognition and Classification Models Enhanced Explainability: Perspectives and Challenges

Author

Héloïse Remusati, Jean-Marc Le Caillec, Jean-Yves Schneider, Jacques Petit-Frère, and Thomas Merlet

Subjects
explanation, neural networks, radar target recognition, synthetic aperture radar, Science
Abstract

Generative adversarial networks (or GANs) are a specific deep learning architecture often used for different usages, such as data generation or image-to-image translation. In recent years, this structure has gained increased popularity and has been used in different fields. One area of expertise currently in vogue is the use of GANs to produce synthetic aperture radar (SAR) data, and especially expand training datasets for SAR automatic target recognition (ATR). In effect, the complex SAR image formation makes these kind of data rich in information, leading to the use of deep networks in deep learning-based methods. Yet, deep networks also require sufficient data for training. However, contrary to optical images, we generally do not have a substantial number of available SAR images because of their acquisition and labelling cost; GANs are then an interesting tool. Concurrently, how to improve explainability for SAR ATR deep neural networks and how to make their reasoning more transparent have been increasingly explored as model opacity deteriorates trust of users. This paper aims at reviewing how GANs are used with SAR images, but also giving perspectives on how GANs could be used to improve interpretability and explainability of SAR classifiers.

Published
2024
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3. On-Chip Circularly Polarized Circular Loop Antennas Utilizing 4H-SiC and GaAs Substrates in the Q/V Band

Author

Rawad Asfour, Salam K. Khamas, Edward A. Ball, Jo Shien Ng, Guanwei Huang, Rozenn Allanic, Denis Le Berre, Cédric Quendo, Aude Leuliet, and Thomas Merlet

Subjects
array antenna, circular polarization, GaAs, loop antennas, millimeter wave, on-chip antennas, Chemical technology, TP1-1185
Abstract

This paper presents a comprehensive assessment of the performance of on-chip circularly polarized (CP) circular loop antennas that have been designed and fabricated to operate in the Q/V frequency band. The proposed antenna design incorporates two concentric loops, with the outer loop as the active element and the inner loop enhancing the CP bandwidth. The study utilizes gallium arsenide (GaAs) and silicon carbide (4H-SiC) semiconductor wafer substrates. The measured results highlight the successful achievement of impedance matching at 40 GHz and 44 GHz for the 4H-SiC and GaAs substrates, respectively. Furthermore, both cases yield an axial ratio (AR) of less than 3 dB, with variations in bandwidths and frequency bands contingent upon the dielectric constant of the respective substrate material. Moreover, the outcomes confirm that utilizing 4H-SiC substrates results in a significantly higher radiation efficiency of 95%, owing to lower substrate losses. In pursuit of these findings, a 4-element circularly polarized loop array antenna has been fabricated for operation at 40 GHz, employing a 4H-SiC wafer as a low-loss substrate. The results underscore the antenna’s remarkable performance, exemplified by a broadside gain of approximately 9.7 dBic and a total efficiency of circa 92%. A close agreement has been achieved between simulated and measured results.

Published
2024
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11. Thermally conductive and leakage-proof phase-change materials composed of dense graphene foam and paraffin for thermal management

Author

Hongling Li, Roland Yingjie Tay, Siu Hon Tsang, Romain Hubert, Philippe Coquet, Thomas Merlet, Jerome Foncin, Jong Jen Yu, Edwin Hang Tong Teo, School of Electrical and Electronic Engineering, CNRS International NTU THALES Research Alliances, Temasek Laboratories @ NTU, Research Techno Plaza, Nanyang Technological University [Singapour], Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Université catholique de Lille (UCL)-Université catholique de Lille (UCL), CNRS International - NTU - Thales Research Alliance (CINTRA), THALES [France]-Nanyang Technological University [Singapour]-Centre National de la Recherche Scientifique (CNRS), THALES Airborne Systems [Elancourt], THALES [France], Thales LAS France, Thales Air Systems, and The authors would like to acknowledge the financial support from Thales.

Subjects
[SPI]Engineering Sciences [physics], Materials [Engineering], Dense Graphene Foam, Latent Heat, General Materials Science, dense graphene foam, thermal conductivity, thermal management, latent heat, composite phase-change material
Abstract

Practical implementation of porous carbon-based composite phase-change materials (CPCMs) for heat dissipation in high-power-density electronics is usually limited by liquid leakage issues and unsatisfactory thermal conductivity resulting from their relatively low filler fraction and/or existence of interfacial thermal resistance between fillers. Therefore, development of shape-stable CPCMs with high thermal conductivity and large latent heat to avoid overheating of electronics remains challenging. Herein, graphene foams (GFs) with very high densities of up to 204 mg/cm3have been synthesized to act as interconnected porous networks of CPCMs. Notably, the obtained CPCM with a filler loading of 11.1 wt % preserves a high heat capacity (171.8 J/g) with a retention of 84.8% while showing a 22.6-fold enhancement in the thermal conductivity as compared to pure PCM (10.13 vs 0.43 W/m·K). A higher thermal conductivity of 14.29 W/m·K can be achieved by further increasing the filler loading to 17.7 wt %, which outperforms many of the previously reported CPCMs based on the interconnected porous carbon-based frameworks. Owing to the superior interconnected network structure of the dense GFs and the strong interconnection between them and PCM molecules, these CPCMs also exhibit leakage-proof shape stability and excellent thermal reliability (at least 100 cycles). Moreover, a state-of-the-art aluminum (Al) package based on the CPCM (filler loading: 11.1 wt %) possessing weight 60% less than its pure Al panel counterpart has been demonstrated to verify better heat transfer efficiency and more efficient phonon pathways of the CPCM composite than those of the pure PCM, which holds great promise for advanced thermal management of emerging applications in electronics. The authors would like to acknowledge the financial support from Thales.

Published
2022
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14. Optimization of PCM based thermal management device for power electronics using an effective thermal conductivity model for architected enhancers

Author

Thomas Merlet, Edwin Hang Tong Teo, Dunlin Tan, Jerome Foncin, Hongling Li, Romain Hubert, Philippe Pernod, Philippe Coquet, Jong Jen Yu, Olivier Bou-Matar, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Acoustique Impulsionnelle & Magnéto-Acoustique Non linéaire - Fluides, Interfaces Liquides & Micro-Systèmes - IEMN (AIMAN-FILMS - IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), CNRS International NTU THALES Research Alliance (UMI CINTRA), THALES-Nanyang Technological University [Singapour]-Centre National de la Recherche Scientifique (CNRS), CINTRA / SEEE Nanyang Technological University, Nanyang Technological University [Singapour], Thales Air Systems, Thales Group [France], Université catholique de Lille (UCL)-Université catholique de Lille (UCL), THALES [France], Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), CNRS International - NTU - Thales Research Alliance (CINTRA), THALES [France]-Nanyang Technological University [Singapour]-Centre National de la Recherche Scientifique (CNRS), and The authors would like to thank Djamila BAHLOUL-HOURLIER (IEMN, CNRS) for her help in the Differential Scanning Calorimetry measurements.

Subjects
melting, Materials science, Enthalpy of fusion, thermal energy storage, Enclosure, latent heat, Conductivity, Thermal energy storage, 7. Clean energy, Phase-change material, [SPI]Engineering Sciences [physics], Thermal conductivity, phase change materials, thermal management (packaging), Latent heat, Power electronics, thermal conductivity, Composite material
Abstract

International audience; Phase Change Material (PCM) have been widely used for thermal energy storage due to their high latent heat of fusion. Several types of PCM are available and can be selected to meet the required melting temperature and latent heat value. However their low thermal conductivity drastically reduces their performances. Without thermal conductivity enhancement, melting would mainly occur at the interface between the heated surface and the PCM, and would slowly spread in the bulk of the PCM. In that sens the use of fillers is necessary. We present here a study on the use of metallic lattice structure as PCM enhancers. In this paper we illustrate the use of a Effective Thermal Conductivity (ETC) model for four different lattice structures to optimize a PCM based device for the thermal management of power electronics. The optimization is done in terms of device overall dimensions (especially its height) but also in term of composite (or enhanced PCM) enclosure. Actually the composite needs to be enclosed to avoid leaking but the enclosure also serves a heat spreading role which is studied here.

Published
2021
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15. Design of a Slotted Waveguide Antenna Based on TE20 Mode in Ku-Band Suitable for Direct Metal Laser Sintering

Author

Youssef Chairi, Sarra Abedrrabba, Rozenn Allanic, Anne-Charlotte Amiaud, Ahmed El Oualkadi, Cédric Quendo, Thomas Merlet, Kamal Reklaoui, and Thierry Le Gouguec

Subjects
Computer Networks and Communications, Hardware and Architecture, Control and Systems Engineering, Signal Processing, 3D printing, antenna arrays, direct metal laser sintering, feeding network, mode converter, slotted waveguide antenna, Electrical and Electronic Engineering
Abstract

This paper describes the design of a novel Ku-band slotted waveguide antenna (SWA), taking into consideration the advantages and drawbacks of using a 3D direct metal laser sintering (DMLS) process. Indeed, the DMLS process makes it possible to produce a SWA with 64 radiating slots and its feeding network in a single and monolithic process. However, considering the lack of accuracy of the process, the whole design must be completely thought out and planned to avoid sensitive dimensions. Coupling irises inside such structures are elements of major sensitivity in this regard, so the radiating waveguides in the present work were designed to be TE20 ones, avoiding this kind of iris. Thus, a TE10 to TE20 converter was designed to be implemented in the overall power supply structure of an antenna array made up of four linear SWAs with 16 slots each. Both the elementary 16-slot SWA and the complete SWA with the feeding network were manufactured using DMLS. At a resonant frequency of 15 GHz, the measured realized gain is 22.26 dB with sidelobe levels below 10.1 dB. The measured reflection coefficient is lower than −12.6 dB at the center frequency. These measured performances confirm the proof of concept.

Published
2022
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16. Explainability of Deep SAR ATR Through Feature Analysis

Author

Alessio Balleri, Carole Belloni, Thomas Merlet, Nabil Aouf, Jean-Marc Le Caillec, Centre for Electronic Warfare, Cranfield University, Defence Academy of the United Kingdom, Shrivenham, SN6 8LA, UK, Département lmage et Traitement Information (IMT Atlantique - ITI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), City University of London, Equipe Marine Mapping & Metrology (Lab-STICC_M3), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), and THALES

Subjects
Synthetic aperture radar, Computer science, Feature extraction, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Aerospace Engineering, 02 engineering and technology, Convolutional neural network, law.invention, Deep Learning, Automatic target recognition, 0203 mechanical engineering, [STAT.ML]Statistics [stat]/Machine Learning [stat.ML], law, Electrical and Electronic Engineering, Radar, [STAT.CO]Statistics [stat]/Computation [stat.CO], Physics::Atmospheric and Oceanic Physics, Features, ComputingMilieux_MISCELLANEOUS, 020301 aerospace & aeronautics, Orientation (computer vision), business.industry, Deep learning, Pattern recognition, Explainability, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, ComputingMethodologies_PATTERNRECOGNITION, Computer Science::Graphics, ATR, Clutter, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, [MATH.MATH-NA]Mathematics [math]/Numerical Analysis [math.NA], SAR
Abstract

Understanding the decision-making process of deep learning networks is a key challenge that has rarely been investigated for synthetic aperture radar (SAR) images. In this article, a set of new analytical tools is proposed and applied to a convolutional neural network (CNN) handling automatic target recognition on two SAR datasets containing military targets. First, an analysis of the respective influence of target, shadow, and background areas on classification performance is carried out. The shadow appears to be the least used portion of the image affecting the decision process, compared to the target and clutter, respectively. Second, the location of the most influential features is determined with classification maps obtained by systematically hiding specific target parts and registering the associated classification rate relative to the images to be classified. The location of the image areas without which classification fails is target type and orientation specific. Nonetheless, a strong contribution of specific parts of the target, such as the target top and the areas facing the radar, is noticed. Finally, results show that features are increasingly activated along the CNN depth according to the target type and its orientation, even though target orientation is absent from the loss function.

Published
2021
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17. Characterisation of sidelobes for multibeam radar based on quasi-orthogonal LFM waveforms

Author

Alessio Balleri, Thomas Merlet, and Leon Kocjancic

Subjects
Computer science, Acoustics, Beam steering, 0211 other engineering and technologies, beam steering, 02 engineering and technology, 01 natural sciences, Ku band, radar antennas, law.invention, Interference (communication), law, Waveform, Radar, array signal processing, 021101 geological & geomatics engineering, Computer Science::Information Theory, FM radar, antenna radiation patterns, 010401 analytical chemistry, radar signal processing, Noise floor, 0104 chemical sciences, Transmission (telecommunications), antenna arrays, Antenna (radio)
Abstract

Multibeam radars (MBRs) enable multiple independent channels by simultaneously exploiting spatial and waveform diversity. Orthogonal waveforms are employed to form multiple independent antenna beams, each one providing a different function and using different dedicated radar resources. This paper investigates sidelobe levels in MBRs and presents a comparison with those of an Electronic Steerable Array (ESA) that employs a single waveform in transmission to generate multiple simultaneous beams. Simulations are carried out for a 3-channel MBR transmitting quasi-orthogonal Linear Frequency Modulated (LFM) waveforms at Ku band. The response of the MBR to an ideal point target as a function of aspect angle as well as that to multiple targets in different locations has been investigated. Results corroborate the analytical findings and show that the sidelobe levels with respect to angle, at the target range, are attenuated by the cross-ambiguity function properties between the waveforms employed. The range response to a target in low channel isolation suffers from cross-channel interference that may alter the noise floor characteristics of the radar, hence stressing the importance of suitable waveform selection.

Published
2020

18. Multibeam radar based on linear frequency modulated waveform diversity

Author

Leon Kocjancic, Alessio Balleri, and Thomas Merlet

Subjects
Computer science, Acoustics, 02 engineering and technology, radar antennas, law.invention, 0203 mechanical engineering, law, diversity reception, 0202 electrical engineering, electronic engineering, information engineering, Chirp, Waveform, Electrical and Electronic Engineering, Radar, signal processing, Digital signal processing, 020301 aerospace & aeronautics, Signal processing, optical modulation, FM radar, business.industry, 020206 networking & telecommunications, pulse compression, radar signal processing, frequency modulation, Transmission (telecommunications), Pulse compression, chirp modulation, business, Frequency modulation
Abstract

Multibeam radar (MBR) systems based on waveform diversity require a set of orthogonal waveforms in order to generate multiple channels in transmission and extract them efficiently at the receiver with digital signal processing. Linear frequency modulated (LFM) signals are extensively used in radar systems due to their pulse compression properties, Doppler tolerance, and ease of generation. Here, the authors investigate the level of isolation between MBR channels based on LFM chirps with rectangular and Gaussian amplitude envelopes. The orthogonal properties and the mathematical expressions of the isolation are derived as a function of the chirp design diversity, and specifically for diverse frequency slopes and frequency offsets. The analytical expressions are validated with a set of simulations as well as with experiments at C-band using a rotating target.

Published
2018
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20. Pose-informed deep learning method for SAR ATR

Author

Jean-Marc Le Caillec, Alessio Balleri, Nabil Aouf, Carole Belloni, Thomas Merlet, Lab-STICC_IMTA_CID_PRASYS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département lmage et Traitement Information (IMT Atlantique - ITI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)

Subjects
Synthetic aperture radar, Computer science, TK, [QFIN.PM]Quantitative Finance [q-fin]/Portfolio Management [q-fin.PM], ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, Convolutional neural network, [QFIN.CP]Quantitative Finance [q-fin]/Computational Finance [q-fin.CP], Hough transform, law.invention, Automatic target recognition, radar target recognition, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, [STAT.CO]Statistics [stat]/Computation [stat.CO], ComputingMilieux_MISCELLANEOUS, Artificial neural network, Contextual image classification, business.industry, Deep learning, Hough transforms, 020206 networking & telecommunications, Pattern recognition, [QFIN.ST]Quantitative Finance [q-fin]/Statistical Finance [q-fin.ST], Target acquisition, radar imaging, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, neural nets, ComputingMethodologies_PATTERNRECOGNITION, image recognition, learning (artificial intelligence), Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, [STAT.ME]Statistics [stat]/Methodology [stat.ME], synthetic aperture radar, image classification
Abstract

Synthetic aperture radar (SAR) images for automatic target classification (automatic target recognition (ATR)) have attracted significant interest as they can be acquired day and night under a wide range of weather conditions. However, SAR images can be time consuming to analyse, even for experts. ATR can alleviate this burden and deep learning is an attractive solution. A new deep learning Pose-informed architecture solution, that takes into account the impact of target orientation on the SAR image as the scatterers configuration changes, is proposed. The classification is achieved in two stages. First, the orientation of the target is determined using a Hough transform and a convolutional neural network (CNN). Then, classification is achieved with a CNN specifically trained on targets with similar orientations to the target under test. The networks are trained with translation and SAR-specific data augmentation. The proposed Pose-informed deep network architecture was successfully tested on the Military Ground Target Dataset (MGTD) and the Moving and Stationary Target Acquisition and Recognition (MSTAR) datasets. Results show the proposed solution outperformed standard AlexNets on the MGTD, MSTAR extended operating condition (EOC)1, EOC2 and standard operating condition (SOC)10 datasets with a score of 99.13% on the MSTAR SOC10.

Published
2020
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21. DRAGON: Adaptive RF Seekers based on 3D Conformal Antennas

Author

Madhubrata Chatterjee, Sarra Abedrrabba, Kenan Ahiska, Cédric Quendo, Thomas Merlet, Rozenn Allanic, Alessio Balleri, Lab-STICC_UBO_MOM_DIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Centre for Electronic Warfare (Cranfield University) (CEW), and Thales LAS France

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Phased array, Computer science, Conformal antenna, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Waveform, 020206 networking & telecommunications, Conformal map, 02 engineering and technology, ComputingMilieux_MISCELLANEOUS, [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

In DRAGON, novel 3-D-shaped conformal antenna arrays are investigated to exploit the ability of an RF seeker to diversify, select and optimize the transmitted waveform design and the 3-D phased array beam-pattern characteristics on a scan to scan basis.The goal of DRAGON is to develop a new solution, which is based on the use of 3-D conformal antennas that are capable to operate with different waveform parameters. Optimization of waveform parameters will provide a strategy to improve prosecution trajectories.

Published
2019

22. Micro-Doppler Signature Extraction with Multibeam Radar

Author

Leon Kocjancic, Thomas Merlet, and Alessio Balleri

Subjects
020301 aerospace & aeronautics, Computer science, Acoustics, 0211 other engineering and technologies, Short-time Fourier transform, 02 engineering and technology, Signal, Signature (logic), law.invention, symbols.namesake, Fourier transform, 0203 mechanical engineering, Interference (communication), law, symbols, Waveform, Radar, Computer Science::Information Theory, 021101 geological & geomatics engineering, Communication channel
Abstract

Orthogonal and quasi-orthogonal waveforms are used in a multibeam radar (MBR) to isolate different channels and reduce cross-channel interference. Each channel provides an independent radar beam that performs a specific functionality without interfering with adjacent channels. The MBR signal model is presented that shows how spatial and waveform diversity are employed to successfully separate multiple channels. In this paper, the theoretical predictions of channel isolation are experimentally confirmed with an analysis of micro-Doppler signatures of a rotating target obtained by applying short-time Fourier transform (STFT).

Published
2019
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23. SAR Specific Noise Based Data Augmentation for Deep Learning

Author

Nabil Aouf, Jean-Marc Le Caillec, Carole Belloni, and Thomas Merlet

Subjects
Synthetic aperture radar, 020301 aerospace & aeronautics, Training set, Computer science, business.industry, Deep learning, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Pattern recognition, 02 engineering and technology, Translation (geometry), Noise, Speckle pattern, Automatic target recognition, 0203 mechanical engineering, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Artificial intelligence, business, Weibull distribution
Abstract

Deep learning techniques provide a significant performance increase in automatic target recognition (ATR) of synthetic aperture radar (SAR) images. Due to acquisition complexity, SAR images are often scarce and the performance of deep learning methods is strongly affected by the lack of diversity and low number of images available for training. Data augmentation is a solution that tackles the problem of reduced data by artificially expanding a training set.In this paper, we propose a data augmentation solution that adds Weibull noise to the High Range Resolution Profiles before SAR processing. The resulting noisy images are added to the original training set. A standard CNN is used to evaluate the impact of the proposed data augmentation on the Cranfield University Military Ground Target Dataset (MGTD). The analysis of performance shows are compared with those obtained with the classic translation data augmentation. Results show a 91% correct classification rate is achieved when a combination of the translation and the Weibull noise data augmentation is employed, compared to 86% with a classic translation data augmentation alone and 77% on standard images without data augmentation.

Published
2019
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24. Numerical characterisation of quasi-orthogonal piecewise linear frequency modulated waveforms

Author

Thomas Merlet, Leon Kocjancic, and Alessio Balleri

Subjects
Piecewise linear function, Degree (graph theory), Product (mathematics), Waveform, Doppler tolerance, Topology, Mathematics
Abstract

This paper presents an analysis of the Doppler tolerance and isolation properties of five different sets of piecewise linear frequency modulated (PLFM) waveform triplets consisting of a combination of LFM subchirps. Different combinations of PLFM signals are used to produce waveforms with the same time-bandwidth product and optimise them with respect to isolation. The performance of the proposed waveforms are numerically investigated and a comparison between sets is presented. Results confirm that the waveforms have quasi-orthogonal properties and exhibit a degree of Doppler tolerance.

Published
2019

25. Experiments of Quasi-Orthogonal Linear Frequency Modulated Waveforms for Multibeam Radar

Author

Thomas Merlet, Leon Kocjancic, and Alessio Balleri

Subjects
Computer science, Acoustics, Gaussian, Bandwidth (signal processing), 0211 other engineering and technologies, 020206 networking & telecommunications, 02 engineering and technology, law.invention, symbols.namesake, Independent channels, law, 0202 electrical engineering, electronic engineering, information engineering, symbols, Chirp, Waveform, Radar, Doppler effect, Frequency modulation, 021101 geological & geomatics engineering
Abstract

Multibeam radars (MBR) enable multiple independent channels by simultaneously exploiting spatial and waveform diversity. The use of orthogonal waveforms is employed to form multiple independent antenna beams, each one providing a different function using diverse radar resources. In this paper, the analytical derivations of the isolation between pseudo-orthogonal rectangular and Gaussian linear frequency modulated (LFM) waveforms are presented. Experiments are conducted to verify the analytical results for chirp pairs with different slopes and various time-bandwidth products at C-band. Experimental results are presented for a direct transmission reception loop and for a moving target to account for Doppler shift contributions.

Published
2019
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26. Comparison of Descriptors for SAR ATR

Author

Nabil Aouf, Thomas Merlet, Carole Belloni, and Jean-Marc Le Caillec

Subjects
Synthetic aperture radar, business.industry, Computer science, Feature extraction, Detector, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Scale-invariant feature transform, Pattern recognition, Image segmentation, Mixture model, Target acquisition, ComputingMethodologies_PATTERNRECOGNITION, Automatic target recognition, Clutter, Artificial intelligence, business
Abstract

Recent studies have reported very high automatic target recognition (ATR) rates of synthetic aperture radar (SAR) images based on the Moving and Stationary Target Acquisition and Recognition (MSTAR) database. However, one of the limitations of the MSTAR database is known correlation between clutter contribution in the training and testing sets. In this paper, we propose an ATR method that consists of a machine learning segmentation based on an evolutive Gaussian Mixture Model (GMM), followed by a feature based classification. The use of segmentation results in a reduction of clutter correlation and computational time. A comparison of performance between different descriptors is presented with special emphasis on binary features, such as Binary Robust Invariant Scalable Keypoints (BRISK). Results show the proposed method achieves a 93.41% probability of correct classification when 3 targets in the Standard Operating Condition (SOC) ATR dataset are tested. Results also show this approach is less sensitive to clutter than methods employing gradient features, such as Scale Invariant Feature Transform (SIFT) or Speeded Up Robust Features (SURF), and template methods.

Published
2019
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27. An effective thermal conductivity model for architected phase change material enhancer: Theoretical and experimental investigations

Author

Hongling Li, Jerome Foncin, Philippe Pernod, Thomas Merlet, Edwin Hang Tong Teo, Romain Hubert, Philippe Coquet, Dunlin Tan, Olivier Bou Matar, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Acoustique Impulsionnelle & Magnéto-Acoustique Non linéaire - Fluides, Interfaces Liquides & Micro-Systèmes - IEMN (AIMAN-FILMS - IEMN), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), CNRS International NTU THALES Research Alliance (UMI CINTRA), THALES-Nanyang Technological University [Singapour]-Centre National de la Recherche Scientifique (CNRS), CINTRA / SEEE Nanyang Technological University, Nanyang Technological University [Singapour], THALES, Laboratoire International associé sur les phénomènes Critiques et Supercritiques en électronique fonctionnelle, acoustique et fluidique (LIA LICS/LEMAC), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), The authors are grateful to the financial support of Thales Land and Air System and the Agence Nationale Recherche Technologie (ANRT )., Université catholique de Lille (UCL)-Université catholique de Lille (UCL), Université catholique de Lille (UCL)-Université catholique de Lille (UCL)-Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), CNRS International - NTU - Thales Research Alliance (CINTRA), THALES [France]-Nanyang Technological University [Singapour]-Centre National de la Recherche Scientifique (CNRS), and Thales LAS France

Subjects
Materials science, 02 engineering and technology, Thermal energy storage, 7. Clean energy, 01 natural sciences, [SPI.MAT]Engineering Sciences [physics]/Materials, 010305 fluids & plasmas, [SPI]Engineering Sciences [physics], Thermal conductivity, 0103 physical sciences, Thermal, Effective thermal conductivity, Cellular materials Homogenization, Porosity, Fluid Flow and Transfer Processes, Mechanical Engineering, Mechanics, Flash laser method, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Phase change materials, Phase-change material, Thermal constriction, 13. Climate action, Heat spreader, Heat equation, 0210 nano-technology, Porous medium
Abstract

International audience; Phase Change Materials (pcm) have been widely used for thermal energy storage due to their high latent heat of fusion. However, PCMs suffer from their very low thermal conductivity which limits heat spreading around the heat source. Without proper thermal conductivity enhancement, melting would occur mainly around the heat source and heat would be conducted too slowly for the device to be efficient. It is especially true when dealing with high power densities. Metallic foams are usually used as thermal conductivity enhancer, yet recent progress in additive manufacturing have allowed architected structures to be used and optimized. We present here an analytical investigation of the Effective Thermal Conductivity (etc) of porous architected structures and emphasize is made on the effect of thermal constriction at the interface with a heat spreader in contact with the heat source. To confirm the efficiency of the model, it is compared to simulation data as well as experimental data obtained using flash laser method. Flash laser method data processing had to be modified to adapt to the porous media being characterized. For that purpose, a 1D finite difference model has been developed to solve the heat equation under flash laser conditions and derive the porous material effective properties. Using this model, architected structure were proven to have an ETC up to 75% higher than the one of foam for similar porosity in particular direction of space. The validity of the above mentioned model where proven through simulation, giving an almost perfect match and experiments detailed in this paper,which showed a maximum deviation of 11%.

Published
2021
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28. Antenne à fentes à cavité en technologie additive pour des applications de réseaux d’antennes adaptatifs

Author

Sarra Abedrrabba, Rozenn ALLANIC, Cédric Quendo, Annaig Martin-Guennou, Julien Haumant, Gwendal Cochet, Yves Quéré, Thomas Merlet, Quendo, Cedric, Lab-STICC_UBO_MOM_DIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Elliptika, and Thales LAS France

Subjects
[SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, [SPI.ELEC] Engineering Sciences [physics]/Electromagnetism, ComputingMilieux_MISCELLANEOUS, [SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

International audience

Published
2019

29. Directivity and ellipticity study for planar and 3D conformal RF-seeker antennas

Author

Eric Rius, Thomas Merlet, Christian Person, Guillaume Lesueur, Annaig Martin-Guennou, Yves Quéré, Luc Fourtinon, Alessio Balleri, Lab-STICC_IMTA_MOM_DIM, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance ( Lab-STICC ), École Nationale d'Ingénieurs de Brest ( ENIB ) -Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -ENSTA Bretagne-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ) -Université Bretagne Loire ( UBL ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ) -École Nationale d'Ingénieurs de Brest ( ENIB ) -Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -ENSTA Bretagne-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ) -Université Bretagne Loire ( UBL ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), Département Micro-Ondes ( MO ), IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), Centre for Electronic Warfare (Cranfield University) ( CEW ), Université de Brest ( UBO ), Thales optronique lasers (Entreprise), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département Micro-Ondes (IMT Atlantique - MO), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre for Electronic Warfare (Cranfield University) (CEW), Université de Brest (UBO), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)

Subjects
Physics, Main lobe, Acoustics, 020208 electrical & electronic engineering, 020206 networking & telecommunications, 02 engineering and technology, 7. Clean energy, Directivity, [SPI.TRON]Engineering Sciences [physics]/Electronics, [ SPI.TRON ] Engineering Sciences [physics]/Electronics, Mechanical system, Azimuth, Planar, Orientation (geometry), 0202 electrical engineering, electronic engineering, information engineering, Antenna (radio), Invariant (mathematics)
Abstract

International audience; Current RF-seekers use a mechanical system to steer the antenna. Instead, 3D conformal antennas coupled to electronically steering demonstrate strong advantages such as a faster steering and a higher coverage. In this paper, the pros and cons of different 2D and 3D array arrangements, the elements orientation and the beamsteering effect are investigated. As part of the specifications, a high azimuthal invariant directivity and a low ellipticity are sought in the direction of the main lobe.

Published
2017
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30. Direct metal laser sintering process investigation: application to 3D slotted waveguide antennas

Author

Christian Person, Guillaume Lesueur, Eric Rius, Annaig Martin-Guennou, Yves Quéré, Thomas Merlet, Shaima Enouz-Vedrenne, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), Thales research and technology (TRT), Thales Optronique S.A. (TOSA), and THALES

Subjects
Fabrication, Materials science, 020208 electrical & electronic engineering, Process (computing), Mechanical engineering, 020206 networking & telecommunications, Conformal map, 02 engineering and technology, Ku band, law.invention, [SPI.TRON]Engineering Sciences [physics]/Electronics, [SPI.MAT]Engineering Sciences [physics]/Materials, Selective laser sintering, [SPI]Engineering Sciences [physics], Machining, Direct metal laser sintering, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, ComputingMilieux_MISCELLANEOUS, Slotted waveguide
Abstract

Increasing demand for the development of multifunction radio-frequency-systems requires the fabrication of complex architectures. Three-dimensional (3D) direct metal printing direct metal laser sintering (DMLS) has the required properties to build complex and robust parts. To determine whether this technology is able to replace traditional machining methods, it needs to be extensively examined. In the present study, several waveguides operating in a wide-frequency range, and slotted waveguide antennas with relevant details and shape, operating in the Ku-band, were designed, machined, assessed and measured. Measurements show that the degradation of component performances are related to the fabrication strategy used. Deterministic defects were observed that make it possible to conceive ways of enhancing manufactured parts. Through this analysis, the authors demonstrate the potential of the DMLS process to construct finely detailed complex and conformal structures.

Published
2017

31. SAR Image Segmentation with GMMs

Author

J.-M. Le Caillec, Carole Belloni, Nabil Aouf, Thomas Merlet, Lab-STICC_IMTA_CID_PRASYS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), Département lmage et Traitement Information (IMT Atlantique - ITI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre for Electronic Warfare (Cranfield University) (CEW), Thales optronique lasers (Entreprise), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance ( Lab-STICC ), École Nationale d'Ingénieurs de Brest ( ENIB ) -Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -ENSTA Bretagne-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ) -Université Bretagne Loire ( UBL ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ) -École Nationale d'Ingénieurs de Brest ( ENIB ) -Université de Bretagne Sud ( UBS ) -Université de Brest ( UBO ) -ENSTA Bretagne-Institut Mines-Télécom [Paris]-Centre National de la Recherche Scientifique ( CNRS ) -Université Bretagne Loire ( UBL ) -IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), Département lmage et Traitement Information ( ITI ), IMT Atlantique Bretagne-Pays de la Loire ( IMT Atlantique ), Centre for Electronic Warfare (Cranfield University) ( CEW ), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)

Subjects
Synthetic aperture radar, 020301 aerospace & aeronautics, Channel (digital image), Computer science, business.industry, TK, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, Pattern recognition, 02 engineering and technology, Image segmentation, [ SPI.SIGNAL ] Engineering Sciences [physics]/Signal and Image processing, Mixture model, Target acquisition, 0203 mechanical engineering, Market segmentation, Feature (computer vision), 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Segmentation, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; This paper proposes a new approach for Synthetic Aperture Radar (SAR) image segmentation. Segmenting SAR images can be challenging because of the blurry edges and the high speckle. The segmentation proposed is based on a machine learning technique. Gaussian Mixture Models (GMMs) were already used to segment images in the visual field and are here adapted to work with single channel SAR images. The segmentation suggested is designed to be a first step towards feature and model based classification. The recall rate is the most important as the goal is to retain most target's features. A high recall rate of 88%, higher than for other segmentation methods on the Moving and Stationary Target Acquisition and Recognition (MSTAR) dataset, was obtained. The next classification stage is thus not affected by a lack of information while its computation load drops. With this method, the inclusion of disruptive features in models of targets is limited, providing computationally lighter models and a speed up in further classification as the narrower segmented areas foster convergence of models and provide refined features to compare. This segmentation method is hence an asset to template, feature and model based classification methods. Besides this method, a comparison between variants of the GMMs segmentation and a classical segmentation is provided.

Published
2017
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32. SAR image dataset of military ground targets with multiple poses for ATR

Author

Thomas Merlet, Alessio Balleri, Jean-Marc Le Caillec, Nabil Aouf, Carole Belloni, Lab-STICC_IMTA_CID_PRASYS, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Département lmage et Traitement Information (IMT Atlantique - ITI), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre for Electronic Warfare (Cranfield University) (CEW), Thales optronique lasers (Entreprise), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), and Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)

Subjects
Synthetic aperture radar, 02 engineering and technology, 01 natural sciences, Signal, 010309 optics, Set (abstract data type), ISAR, Automatic target recognition, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Range (statistics), Waveform, Computer vision, Remote sensing, business.industry, MGTD, Bandwidth (signal processing), Inverse synthetic aperture radar, Geography, ATR, 020201 artificial intelligence & image processing, Artificial intelligence, business, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing, SAR, Dataset
Abstract

International audience; Automatic Target Recognition (ATR) is the task of automatically detecting and classifying targets. Recognition using Synthetic Aperture Radar (SAR) images is interesting because SAR images can be acquired at night and under any weather conditions, whereas optical sensors operating in the visible band do not have this capability. Existing SAR ATR algorithms have mostly been evaluated using the MSTAR dataset. 1 The problem with the MSTAR is that some of the proposed ATR methods have shown good classification performance even when targets were hidden, 2 suggesting the presence of a bias in the dataset. Evaluations of SAR ATR techniques are currently challenging due to the lack of publicly available data in the SAR domain. In this paper, we presenta high resolution SAR dataset consisting of images of a set of ground military target models taken at various aspect angles, The dataset can be used for a fair evaluation and comparison of SAR ATR algorithms. We applied the Inverse Synthetic Aperture Radar (ISAR) technique to echoes from targets rotating on a turntable and illuminated with a stepped frequency waveform. The targets in the database consist of four variants of two 1.7m-long models of T-64 and T-72 tanks. The gun, the turret position and the depression angle are varied to form 26 different sequences of images. The emitted signal spanned the frequency range from 13 GHz to 18 GHz to achieve a bandwidth of 5 GHz sampled with 4001 frequency points. The resolution obtained with respect to the size of the model targets is comparable to typical values obtained using SAR airborne systems. Single polarized images (Horizontal-Horizontal) are generated using the backprojection algorithm. 3 A total of 1480 images are produced using a 20 ° integration angle. The images in the dataset are organized in a suggested training and testing set to facilitate a standard evaluation of SAR ATR algorithm

Published
2017
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33. Study of the Frequency Slope Effect on the Chirp Waveform Orthogonality

Author

Thomas Merlet, L. Kocjancic, and Alessio Balleri

Subjects
business.industry, Computer science, Acoustics, 020206 networking & telecommunications, 02 engineering and technology, Function (mathematics), Set (abstract data type), Orthogonality, Transmission (telecommunications), Pulse compression, 0202 electrical engineering, electronic engineering, information engineering, Chirp, Waveform, ComputerSystemsOrganization_SPECIAL-PURPOSEANDAPPLICATION-BASEDSYSTEMS, business, Digital signal processing
Abstract

Multiple-Beam Radar Systems (MBRS) based on waveform diversity require a set of orthogonal waveforms in order to generate multiple channels in transmission and extract them efficiently at the receiver using digital signal processing. Chirp signals are extensively used in radar systems due to their pulse compression properties, Doppler tolerance and ease of generation. In this paper, we investigate the level of isolation between two linear frequency modulated (LFM) chirps as a function of the frequency slope and of the chirp starting frequency. Results are derived analytically and verified with a set of measurements at S-band.

Published
2017
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34. Design and manufacturing of a 3-D conformal slotted waveguide antenna array in Ku-band based on Direct Metal Laser Sintering

Author

Yves Quéré, Thomas Merlet, L. Fourtinon, Christian Person, A. Guennou-Martin, Eric Rius, Guillaume Lesueur, Lab-STICC_UBO_MOM_DIM, Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO)-Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Mines-Télécom [Paris] (IMT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (UMR 3192) (Lab-STICC), Université européenne de Bretagne - European University of Brittany (UEB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS), Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL), Lab-STICC_TB_MOM_DIM, Thales Optronique S.A. (TOSA), THALES, Institut Mines-Télécom [Paris] (IMT)-École Nationale d'Ingénieurs de Brest (ENIB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-Institut Brestois du Numérique et des Mathématiques (IBNM), and Université de Brest (UBO)

Subjects
Engineering, Reconfigurable antenna, Directional antenna, business.industry, 020208 electrical & electronic engineering, Antenna measurement, Conformal antenna, Electrical engineering, 020206 networking & telecommunications, Slot antenna, 02 engineering and technology, 7. Clean energy, law.invention, [SPI.TRON]Engineering Sciences [physics]/Electronics, Folded inverted conformal antenna, Antenna array, Microstrip antenna, law, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, business, ComputingMilieux_MISCELLANEOUS
Abstract

One of the growing trend in antennas is to address multifunctional systems, providing direct space saving and cost reduction. A consideration for future generation antennas is to replace the classical planar geometry with new functionalities. Three-dimensional (3-D) / conformal antennas offer significant advantages for such system. However, traditional manufacturing processes limit their realization. Additive Manufacturing have been identified as very promising solutions to overcome the dimensional challenge that 3-D components represent. These technologies enable the manufacturing of complex and conformal structures and goes beyond the conventional subtractive manufacturing techniques. In this contribution we propose to evaluate the manufacturing capacities of the Direct Metal Laser Sintering (DMLS). For this purpose, we need an easy-to-test antenna structure containing pertinent features representative of all complication we can run into when designing a complex antenna, including phased array antenna. We propose a conformal slotted waveguide antenna arrays (SWAA) operating in Ku band. The electrical performances of the device have been compared between simulation with ANSYS® HFSS™ software and measurements. Despite a mismatch in the reflection parameter, good results are obtained in gain. They enable us to envision promising future achievements and a better mastering of the global set of parameters.

Published
2016

35. Beampattern and polarisation synthesis of 3D RF-seeker antenna arrays

Author

Luc Fourtinon, Alessio Balleri, Yves Quere, Christian Person, Annaig Martin-Guennou, Eric Rius, Guillaume Lesueur, Thomas Merlet, Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-Université Bretagne Loire (UBL)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT), Centre for Electronic Warfare (Cranfield University) (CEW), and Thales LAS France

Subjects
[SPI]Engineering Sciences [physics], ComputingMilieux_MISCELLANEOUS, [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

International audience

Published
2016

37. Optical multibeamforming network based on WDM and dispersion fiber in receive mode

Author

K. Garenaux, M. Queguiner, Stephane Blanc, Mehdi Alouini, and Thomas Merlet

Subjects
Physics, Mode volume, Radiation, business.industry, Optical cross-connect, Single-mode optical fiber, Physics::Optics, Optical performance monitoring, Condensed Matter Physics, Optics, Wavelength-division multiplexing, Dispersion (optics), Dispersion-shifted fiber, Electrical and Electronic Engineering, business, Plastic optical fiber, Computer Science::Information Theory
Abstract

We present and experimentally demonstrate an optical beamformer for the receive mode based on optical summation and dispersive fiber. This architecture allows a high number of simultaneous beams without multiplying the number of active elements. The incoherent optical summation based on wavelength division multiplexing is analyzed in term of RF dynamic range and validated by experiments

Published
2006
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38. Large Deformable Antennas

Author

Olivier Clouard, Isabelle Barbereau, Sylvain Girard, Mourad Chtioui, Guillaume Lesueur, Hervé Gilles, Thomas Merlet, and Philippe Leprince

Subjects
Materials science, business.industry, Optical instrumentation, Optoelectronics, business
Published
2014
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39. Developement and optimization protocol of an additive phase noise measurement bench dedicated to long-haul microwave analog optical links

Author

Mehdi Alouini, A. Marceaux, Thomas Merlet, Lucien Pouget, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Alcatel-Thalès III-V lab (III-V Lab), THALES-ALCATEL, Thales Air Systems, Thales Group [France], Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), THALES [France]-ALCATEL, and THALES [France]

Subjects
Protocol (science), 020301 aerospace & aeronautics, Engineering, Noise temperature, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Noise measurement, business.industry, Electrical engineering, 02 engineering and technology, 01 natural sciences, Noise floor, 010309 optics, 0203 mechanical engineering, 0103 physical sciences, Phase noise, Electronic engineering, business, Microwave photonics, Noise (radio), Microwave
Abstract

International audience; We propose a microwave additive phase noise measurement scheme dedicated to long-haul microwave analog optical links. We describe here the protocol to follow and precautions to take in order to ensure a reliable measurement with a reduced noise floor level.

Published
2013
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40. A traveling fringes photodetector for microwave signals

Author

D. Dolfi, Thomas Merlet, and J.-P. Huignard

Subjects
Materials science, business.industry, Photoconductivity, Microwave signals, Photodetector, Optical power, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, Power (physics), Gallium arsenide, chemistry.chemical_compound, Optics, chemistry, Electric field, Optoelectronics, Electrical and Electronic Engineering, business, Microwave
Abstract

We report a novel straightforward theoretical analysis and improved high frequency experimental performances of a new type resonant photodetector. A large detection volume is provided by a synchronous drift of photogenerated carriers with a moving interference pattern in a photoconductor. It appears to be suitable for optical generation of microwave signals at high power levels. Performances as a function of applied electric field, photoconductive material characteristic, fringe period, and optical power level are analyzed. Experimental results using a GaAs photoconductive layer are presented at frequency f=1.6 GHz.

Published
1996
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41. High-Spectral Purity RF Beat Note Generated by a Two-Frequency Solid-State Laser in a Dual Thermooptic and Electrooptic Phase-Locked Loop

Author

A. Poezevara, Marc Brunel, J. Brisset, Thomas Merlet, V. Crozatier, S. Blanc, and Fabien Bretenaker

Subjects
Materials science, Physics::Instrumentation and Detectors, business.industry, Physics::Optics, Beat (acoustics), dBc, Laser, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, law.invention, Phase-locked loop, Optics, Solid-state laser, law, Phase noise, Optoelectronics, Electrical and Electronic Engineering, business, Frequency modulation, Spectral purity
Abstract

Ultralow noise stabilization of a two-frequency solid-state laser is experimentally demonstrated using a specially designed dual phase-locked loop. Thanks to an intracavity birefringent crystal providing both thermooptic and electrooptic frequency modulation properties, the laser delivers a beat frequency that is controlled by both pump power and voltage from 0 to 1000 MHz. When phase-locked against a radio-frequency synthesizer, the beat note has a 25-mHz full-width at half-maximum. The measured phase noise is -110 dBc/Hz at 10-kHz offset, and lower than -130 dBc/Hz at 1-MHz offset and above. Improvements and applications to local oscillators in microwave-photonic systems are discussed.

Published
2004
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42. Comparison of theoretical and measured P1dB of a photonic microwave link : influence of some physical parameters of the DFB laser

Author

Catherine Algani, Christian Rumelhard, Mourad Chtioui, Quentin Levesque, Anne-Laure Billabert, Thomas Merlet, A. Marceaux, Algani, Catherine, Electronique, Systèmes de communication et Microsystèmes (ESYCOM), Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, Thales Airborne Systems, THALES Airborne Systems, Alcatel-Thalès III-V lab (III-V Lab), THALES [France]-ALCATEL, Thales Air Systems, THALES [France], Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, THALES-ALCATEL, and Thales Group [France]

Subjects
Distributed feedback laser, Engineering, Oscillation, business.industry, 020206 networking & telecommunications, 02 engineering and technology, Microwave transmission, Laser, Noise (electronics), [SPI.TRON] Engineering Sciences [physics]/Electronics, law.invention, [SPI.TRON]Engineering Sciences [physics]/Electronics, Nonlinear system, 020210 optoelectronics & photonics, Optics, Transducer, law, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Photonics, business
Abstract

International audience; This paper studies a microwave photonic link built as an IM/DD or intensity modulation-direct detection semiconductor laser system. The radiofrequency gain and 1 dB compression point of the link are both simulated with a modelling approach and compared to measurements. The electrical model of the electro-optic transducer, a distributed feedback laser, is first presented. Taking into account the nonlinearities and noise sources, it is developed on the commercial electrical software Advanced Design System. Owing to this accurate model, the impact of the relaxation oscillation frequency is presented on the system nonlinearity characteristic as for example the input 1 dB compression point. The comparison of simulated results to measured ones confirms the accuracy of this model.

Published
2013

43. Stabilized 1.5 microns dual-frequency laser prototype for optical generation of high purity microwave signals

Author

Gregoire Pillet, Bastien Steinhausser, Loic Morvan, Julien Schiellein, Daniel Dolfi, and Thomas Merlet

Subjects
Signal processing, Materials science, business.industry, chemistry.chemical_element, Laser, law.invention, Semiconductor laser theory, Erbium, Optical pumping, Optics, chemistry, law, Phase noise, Optoelectronics, business, Frequency modulation, Microwave
Abstract

The generation of optically carried microwave signals is of great interest for a wide range of fields, from long-range transmission of RF to wideband radar signal processing. Among the available generation techniques, the potentialities of optical heterodyning are firmly established. However, it leads to severe constraints in optical phase-locked loop (OPLL) design. In this paper, we report on the realization of a compact and ruggedized Er, Yb:glass DFL at 1.5 µm stabilized with three servo-loops.

Published
2011
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44. Impact of physical parameters of laser model electrical circuit on gain and IP1dB

Author

Billabert, Anne-Laure, Quentin, Levesque, Algani, Catherine, Mourad, Chtioui, Alexandre, Marceaux, Thomas, Merlet, Billabert, Anne-Laure, Electronique, Systèmes de communication et Microsystèmes (ESYCOM), Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, and Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris

Subjects
[SPI.TRON] Engineering Sciences [physics]/Electronics, [SPI.TRON]Engineering Sciences [physics]/Electronics
Abstract

International audience; This paper presents the electrical model of the electro-optic transducer, a DFB laser, taken into account the non linearity and noise, developed on the commercial electrical software Advanced Design System (ADS). Owing to this accurate model, the impact of the relaxation oscillation frequency is presented on the system non linearity characteristic as for example the input 1dB compression point. The comparison of simulated results to measured one confirms the accuracy of this model

Published
2011

45. Simulation of microwave optical links and proof of noise figure lower than electrical losses

Author

Mourad Chtioui, Catherine Algani, Thomas Merlet, Quentin Levesque, A. Marceaux, Christophe Feuillet, Christian Rumelhard, Anne-Laure Billabert, Mehdi Alouini, Electronique, Systèmes de communication et Microsystèmes (ESYCOM), Conservatoire National des Arts et Métiers [CNAM] (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, Alcatel-Thalès III-V lab (III-V Lab), THALES [France]-ALCATEL, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Thales Airborne Systems, THALES Airborne Systems, Thales Air Systems, THALES [France], Conservatoire National des Arts et Métiers [CNAM] (CNAM)-Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris, THALES-ALCATEL, Thales Group [France], Université Paris-Est Marne-la-Vallée (UPEM)-ESIEE Paris-Conservatoire National des Arts et Métiers [CNAM] (CNAM), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Simulation and characterizations of devices and circuits, Optical link, 020208 electrical & electronic engineering, Impedance matching, Modeling, 020206 networking & telecommunications, 02 engineering and technology, Noise figure, Electrical phenomena, law.invention, [SPI.TRON]Engineering Sciences [physics]/Electronics, law, Electrical network, Microwave photonics, 0202 electrical engineering, electronic engineering, information engineering, Electronic engineering, Microwave noise power measurements, Output impedance, Radio frequency, Electrical and Electronic Engineering, Microwave
Abstract

International audience; The operation of a microwave photonic link is thoroughly investigated both theoretically and experimentally. To this aim, we have developed a simulation tool based on an accurate physical model embedded in a radio frequency (RF) chain simulator. The theoretical predictions are tested on an intensity modulation-direct detection (IMDD) link we have specifically developed to this purpose. Our simulation tool takes into account both optical and electrical characteristics of the link components including the laser dynamics and impedance matching networks. It thus enables an accurate understanding of the different physical and electrical phenomena governing the link's performances even under unusual operation conditions. Specifically, we were able to isolate an unusual behavior and to confirm it experimentally. It is thereby clear that the noise figure of a microwave optical link can be lower than the electrical losses, such as a mismatched output passive electrical network. This state is reached when the optical losses are high enough and when the link's output impedance is mismatched, too.

Published
2010
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46. 40-GHz Photonic Synthesizer Using a Dual-Polarization Microlaser

Author

Ludovic Frein, Thomas Merlet, Marc Vallet, Antoine Rolland, François Bondu, Marc Brunel, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes ( IPR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Materials science, Optical fiber, [ PHYS.PHYS.PHYS-OPTICS ] Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Optical polarization, 02 engineering and technology, 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, law.invention, 010309 optics, Phase-locked loop, Voltage-controlled oscillator, 020210 optoelectronics & photonics, Dual-polarization interferometry, Optics, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Electrical and Electronic Engineering, Photonics, Maser, business, Microwave
Abstract

International audience; An optically carried microwave synthesis working at 40 GHz is demonstrated by using a two-frequency solid-state microchip laser inserted as a voltage-controlled oscillator inside a digital phase-locked loop. We report an in-loop relative frequency stability better than 2.5 × 10-11. The capabilities of the synthesis are illustrated with different frequency sweeping formats.

Published
2010
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47. Stabilization of new generation solid-state dual-frequency laser at 1.5 µm for optical distribution of high purity microwave signals

Author

Daniel Dolfi, Julien Schiellein, Gregoire Pillet, Loic Morvan, and Thomas Merlet

Subjects
Ytterbium, Materials science, Optical fiber, business.industry, Phase (waves), Physics::Optics, chemistry.chemical_element, dBc, Laser, law.invention, Erbium, Optics, chemistry, law, Phase noise, Optoelectronics, Maser, business
Abstract

We report on a compact and ruggedized dual-frequency laser at 1.5 µm delivering widely tunable (0–13 GHz) optically-carried microwave signals with a high stability (phase and amplitude noise below −120 dBc/Hz @10 kHz).

Published
2010
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48. Polarization Optical Sensor for Dynamical Deformation Measurements on 1-D or 2-D Mechanical Structures

Author

Mathieu Laroche, M. Queguiner, Sylvain Girard, G. Lesueur, A. Marciniak, Thomas Merlet, Hervé Gilles, Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Caen Normandie (UNICAEN), Normandie Université (NU), Thales Air Systems, Thales Group [France], Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and THALES [France]

Subjects
Materials science, Optical distortion, optical polarization, Beam steering, ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION, 02 engineering and technology, 020210 optoelectronics & photonics, Optics, [PHYS.MECA.STRU]Physics [physics]/Mechanics [physics]/Structural mechanics [physics.class-ph], Radar antennas, 0202 electrical engineering, electronic engineering, information engineering, Antenna arrays, [PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det], Electrical and Electronic Engineering, optical propagation in anisotropic media, [PHYS.MECA.VIBR]Physics [physics]/Mechanics [physics]/Vibrations [physics.class-ph], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, [SPI.MECA.VIBR]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Vibrations [physics.class-ph], 020206 networking & telecommunications, Optical polarization, Polarization (waves), Atomic and Molecular Physics, and Optics, optical position measurement, Electronic, Optical and Magnetic Materials, [SPI.MECA.STRU]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Structural mechanics [physics.class-ph], business
Abstract

International audience; An optical technique based on light polarization is implemented for real-time distortion measurement on mechanical structures. The method uses a polarization gradient encoding on coherent light beam to produce an absolute reference scale. In order to test the performances of the device, a series of well-controlled distortions on a simple aluminum bar have been successfully reconstructed. This optical sensor is part of a global project for the development of a device for active distortion compensation on electronically steered radar antennas.

Published
2009

49. Why Raman amplification ?

Author

Robert Frey, Daniel Dolfi, Philippe Delaye, Thomas Merlet, Mehdi Alouini, J.-P. Huignard, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Thales Research and Technology [Palaiseau], THALES [France], Thales Air Systems, Laboratoire Charles Fabry de l'Institut d'Optique / Manolia, Laboratoire Charles Fabry de l'Institut d'Optique (LCFIO), Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), DGA, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), THALES, and Thales Group [France]

Subjects
Optical amplifier, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Optical fiber, Materials science, Raman amplification, business.industry, chemistry.chemical_element, Physics::Optics, 02 engineering and technology, Population inversion, 01 natural sciences, Noise (electronics), law.invention, 010309 optics, Erbium, 020210 optoelectronics & photonics, Optics, chemistry, law, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, Radio frequency, Stimulated emission, business
Abstract

International audience; Raman amplification of optically carried RF signals is shown to be a good alternative to erbium-doped-fiber amplification. In the case of continuous RF signal, RIN levels as low as -160 dB/Hz, limited by the laser source, are obtained. Moreover, when the RF signal is no more continuous, such as real radar waveforms, we evidence that Raman amplification overcomes erbium-doped-fiber amplification. Improvement of the pulse-to-pulse RF phase stability of 17 dB is observed. This result is attributed to the nature of Raman amplification, which does not involve transient variations of the population inversion across the whole spectral range covered by radar waveforms.

Published
2008

50. Ultra low microwave additive phase noise for an optical RF link based on a Class-A semiconductor laser

Author

Thierry Malherbe, Daniel Dolfi, Thomas Merlet, Mehdi Alouini, Ghaya Baili, Jean Chazelas, J.-P. Huignard, F. Bretanaker, and Isabelle Sagnes

Subjects
Noise temperature, Materials science, business.industry, Relative intensity noise, Noise spectral density, Quantum noise, Shot noise, Physics::Optics, Noise floor, Optics, Noise generator, Phase noise, Optoelectronics, business
Abstract

The additive RF phase noise of a microwave photonics link is measured using, as the optical source, a semiconductor laser operating in the Class-A regime. The relative intensity noise of this laser being below the shot noise relative level, the phase noise floor of the link is shown to be shot noise limited, -152 dBc/Hz in our experimental conditions. As a result, the phase noise floor evolves as the inverse of the detected photocurrent, pushing the limits of performance to the availability of high power photo-detectors. Below 6 kHz from the carrier frequency at 3 GHz, some noise, in excess with respect to the shot noise limit, is observed but remains lower than -110 dBc/Hz at 100 Hz offset frequency. This residual noise originates mainly from technical noise and can be reduced by isolating the laser from acoustic/electromagnetic perturbations.

Published
2008
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