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International audience; This letter presents a new type of E-band vertically aligned carbon nanotubes (VACNTs)-based air-filled waveguide (AFWG). This original concept is based on the use of bundle of VACNTs as equivalent WG’s metallic lateral walls. The WG is designed by applying a full-wave three dimensions electromagnetic software and an equivalent VACNTs bulk model. Then, the WG is fabricated using a CMOS compatible CNTs transfer process and a dedicated assembly process. For the first time, the concept of the CNTs-based AFWG is validated by measurements, and an experimental attenuation constant is estimated at 0.5 dB/mm between 81 and 86 GHz.

This paper has introduced the concept of UWB antenna in array arrangements. The four elements of Balance Antipodal Vivaldi Antenna (BAVA) has been used for planar and H-plane array configuration in this research. Each single element of BAVA Antenna is printed on the glass-reinforced epoxy laminate material (FR4) along an overall thickness of 1.57mm and εr=4.3 respectively. The optimized measurement of each particular element is 60.75mm x 66mm approximatel. Further the parametric evaluation of four BAVA elements in different planes has been observed in this paper. The placement of array elements has almost coverd entire UWB frequency range and appropriate reflection coefficient which is better than -10dB has been established in both combinations. According to simulation results, the array elements in planar arrangement presenting a suitable reflection and works well at 3.2GHz frequency while the arrangement in H-plane the array elements works well at 7GHz of frequency. In planar arrangement, the operating frequency of antenna elements is shifting as results of the distance among inter elements which increase in wavelength. In H-plane arrangement an antenna elements generate additional gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The CSTMWS simulation software has been used for antenna structural design and parametric verification.

This paper proposes an innovative differential sensor based on planar microwave transducers printed on flexible substrate by low-cost printing technologies and operating at ambient temperature. The gas detection is obtained from a differential approach between a reference channel and gas sensitive one based on PEDOT: PSS-MWCNT. A preliminary sensor is fabricated and tested around 3.6 GHz. The experimental behavior in the presence of ethanol vapor is encouraging and validates the proof-of-concept.

Les technologies du numérique et de l'Intelligence Artificielle (IA) sont amenées à jouer un rôle essentiel dans tous les domaines de la société de demain pour améliorer le fonctionnement de la ville et la qualité de vie de ses habitants, tout en diminuant l'impact environnemental et la facture énergétique globale. Pour atteindre ses objectifs, il est nécessaire de penser les modes de complémentarité entre l'Humain et les systèmes intelligents. En effet, l'IA contribuera à rendre les villes intelligentes et sera vue comme un facteur d'amélioration de la qualité de vie, qui si elle est comprise et acceptée par les citoyens. Ce futur environnement urbain numérique ne peut alors se résumer à un réseau interconnecté de boîtes noires, mais doit tendre vers un réseau intelligent explicable, éthique et centré sur l'Humain. Ce chapitre se place dans ce contexte et propose des pistes de réflexion sur les enjeux numériques et sociétaux de la future ville intelligente.

This paper evaluate the parametric effects due to mutual coupling between inter-elements using balance antipodal Vivaldi antenna (BAVA) with high permittivity dielectric director in an array configuration. An elliptical shaped dielectric-director made by the substrate of Rogers RO-3010 with high permittivity of e r =10.2 is used with BAVA in order to enhance the radiation characteristics of the antenna in focus. An antenna (66mm × 60.75mm) in dimension designed on FR4 substrate, which covers ultra-wide frequency band of 114.28% from 3GHz to 8GHz. The performance of an antenna with dielectric director is evaluated in a capacity of gain enhancement, directivity, regular radiation pattern with low side lobe level and beam width. Further, the use of dielectric directors in planner antenna array based configuration can provide significantly change in radiation characteristic and also provide help in the reduction of mutual coupling inter-elements. The same results can be obtained by using four elements with high permittivity dielectric directors in the planner antenna array based arrangement instead of eight or more elements without directors. This is an alternative way to reduce the number of elements in an antenna array based system. The design and optimization progression is realized out using CST simulation software.

International audience; In this work, we investigate the performances of vertically aligned carbon nanotube (VACNT) arrays for high frequency interconnects. The frequency range of this study is the W band (75 GHz to 110 GHz). The type of interconnect is coplanar, meaning the interconnect can connect two subparts supporting a coplanar waveguide (CPW) mode. Starting from the promising results of a previously measured device [1] we suggest a way to improve the behavior of VACNT arrays interconnects. We perform full-wave modeling of a new structure that will be fabricated and tested and we compare different modelling approaches for the design of such interconnects.

This paper describes a classic architecture of a 4 × 4 Butler matrix in an innovative air-filled waveguide technology based on carbon nanotubes for beam pointing or beam tracking activities for 5G applications. The working frequencies concern particularly the E-band (71-86 GHz). The model used to simulate the waveguides, couplers and crossovers needed for the Butler matrix is presented as well as the expected results in terms of S parameters. The expected insertion loss is extremely low thanks to the considered technology, 0.02 dB/mm in E-band, making the carbon nanotubes very attractive in this context. The transitions that allow connecting the waveguides to planar transmission lines have also been developed and are introduced in this paper. Their maximum insertion losses are 0.6 dB for a matching better than 17 dB over the entire E-band.

International audience; In this paper, we propose to study the influence of moisture on passive radiofrequency (RF) sensors associated with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate - multi walled carbon nanotubes (PEDOT:PSS-MWCNT) as a sensitive material. The designed sensor consists of a copper ring resonator and two PEDOT:PSS-MWCNT stubs located in the maximum electric fields of the fundamental resonant mode operating at 3.94 GHz. For performing a differential analysis, experiments are conducted by considering the resonant structure with and without a sensitive layer. Our experiments show the high interference of humidity on the sensor’s performances and highlight the importance of differential study to decorrelate physical and chemical surrounding parameters. This differential innovative structure paves the way for a very high sensitive passive RF sensor dedicated for gas sensing.

Online publication: 2018Issue date: June 2022; International audience; This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and wireless communication applications. The final aim is to develop a low cost ultra-sensitive sensor that can be integrated into a real time multi-sensing platform. The sensors presented in this article are dedicated to the detection of gases such as volatile organic compounds (VOCs) in order to monitor environmental pollution. Experiments were conducted on two devices D1 and D2 which have different geometries notably on the coupling part between electrodes and the position of the sensitive layer based on nanocomposite material PEDOT: PSS-MWCNTs. The preliminary results have shown a large influence of ethanol vapor concentrations on the electrical properties of the passive resonators that constitute each device in the frequency range from 2 to 4 GHz. The sensors sensitivity to ethanol vapor exposition has been estimated to - 0.2 and - 2.2 kHz/ppm for D1 and D2, respectively, according to the resonant frequency shifts for 500–2000 ppm concentrations. The high sensitive surface of the sensor (D2), with possible further functionalization based on various sensitive materials in a large range of electrical conductivity, make it especially interesting for the development of chemical gas sensors for different applications requiring passive and autonomous components at low cost.

A study on the passive microwave components made by polymer additive manufacturing (polymer jetting) is presented. Different types of components (waveguides, couplers, power dividers, filters and antennas) are designed to be made in a single part. Using a simple and cost-effective metallisation by applying silver paint, various prototypes with complex geometries have been manufactured to evaluate these proofs of concept and the robustness of the low-cost approach to make microwave components. Different measurements show that the obtained filters can provide an acceptable unloaded Q factor of 400–500 for the operating frequencies of 12–22 GHz. Waveguiding structures such as a mode converter, which is used as a broadband antenna, have also notably efficiently worked up to the Ka band (36 GHz). Due to a remarkable accuracy of nearly 80 µm, the obtained results of the proposed coupler, power divider and antennas are consistent with the full wave simulations, which prove that the currently available three-dimensional plastic printers can provide notably accurate prototypes to design original components.

Future electronic trend is faster speed, larger bandwidth, and higher power. These requirements stimulate the operating frequency of microelectronic devices to higher frequency range. Hence, conventional metal used in the interconnection in circuit would inevitably face skin effect and electromigration issues. Carbon nanotube (CNT) has received much attention due to its superior properties in high frequency applications. In this work, CNT array will be used for two packaging solutions: CNT-based TSV and CNT-based flip-chip. They were fabricated using a newly developed low-temperature CMOS-compatible CNT transfer technique. CNT growth was conducted on a donor substrate before CNT bundles were inserted into via holes or transferred onto chip/carrier to form the desired CNT-based device. Therefore, the device fabrication can be separated from high temperature CNT growth. Experimental studies validate CNT as potential material in RF interconnections.

In this work, microwave components were printed on a Kapton (polyimide) substrate using a Drop-On-Demand (DOD) ink jet printer with silver nanoparticle ink. Two different laser curing strategies are presented by implementing selective sintering. The measured improvement of the achieved conductivity is between 70 and 100% for such resonators from 5 to 15 GHz.

A 50 GHz carbon nanotube based rectangular resonant cavity is designed, allowing to experimentally obtain the value of the RF conductivity of high-density CNT forests. It also validates a CMOS compatible fabrication process robust to current leakage. A CNT equivalent bulk model is used for 3D electromagnetic simulations and parametric analysis. A new transfer method of CNT forests is considered for the fabrication of the rectangular cavity resonator.

International audience; This paper presents the feasibility of a fully inkjet-printed, microwave flexible gas sensor based on a resonant electromagnetic transducer in microstrip technology and the impact of the printing process that affects the characteristics of the gas sensor. The sensor is fabricated using silver ink and multi-wall carbon nanotubes (MWCNTs) embedded in poly (3,4-ethylenedioxythiophene) polystyrene (PEDOT: PSS-MWCNTs) as sensitive material for Volatile Organic Compounds (VOCs) detection. Particular attention is paid to the characterization of the printed materials and the paper substrate. The manufacturing process results in a change in relative permittivity of the paper substrate by nearly 20%. Electrical characterization, made in the presence of gas, validates our theoretical approach and the radiofrequency (RF) gas sensor proof of concept.

This paper presents an inkjet-printed differential passive microwave planar resonator-based sensor for toxic vapor detection at room temperature. Two devices are presented, with 5 (D1) and 50 (D2) layers of composite sensitive film (PEDOT:PSS-MWCNTs). Each one consists of two band-pass resonators with the fundamental modes around 2.5 and 2.7 GHz. Theoretical and experimental results are presented, both devices show sensitivity to ethanol vapor ranging from 500 to 1300 ppm according to the magnitude and resonant frequency shifts of their scattering parameters (S-parameters). Limitations due to a continuous drift on both the reference and the sensitive channels are discussed. Though further improvements are needed, such sensor is a good candidate for integration into real-time multi-sensing platforms adaptable for the Internet of Things. This work was supported in part by the French National Research Agency under Project ANR-13-BS03-0010 and in part by the “Investments for the future” Programme IdEx Bordeaux, under Grant ANR-10-IDEX-03-02.

This paper presents a 6th order quasi-elliptic bandpass filter working at 11.75 GHz and based on dielectric hollow resonators (pucks). The resonators and their supporting elements have been fabricated altogether in a single part using ceramic (Alumina) additive manufacturing. This part is simply placed in the filter metal housing and therefore limits the number of pieces to be assembled. An important aspect of this work is that no specific, and potentially lossy, third materials (supports, glue) are needed. This assembly route easily allows the dielectric resonators to be placed in the middle of their cavities in order to maximize their Q factor. The proposed principle has been experimentally validated using, for the fast prototyping of this proof of concept, metallized and low cost plastic 3D printing

In this paper, an Ultra-wideband Balance Antipodal Vivaldi Antenna in planar and h-plane array configuration is presented. The comparison of four elements of BAVA array in both planes has been observed. Each element of an antenna printed on the glass-reinforced epoxy laminate material (FR4) with a thickness of 1.5mm and relative permittivity of 4.3. The dimension of every single element is 60.75mm $\times$ 66mm approximately. The array elements of both planes almost cover the whole UWB frequency range with the reflection coefficient of −10dB. Based on the simulation results, the array elements in planar configuration showing good reflection and works well at 3.2GHz frequency while the configuration in h-plane the array elements works well at 7GHz of frequency. In planar configuration, the operating frequency of antenna elements is shifting as a result of the distance between inter elements which intensification in wavelength. The array elements in h-plane produce more gain up to 10.2 dB with good radiation patterns as compared to the planar plane. The antenna design and optimization development are verified using CST simulation software.

This work describes an overview of antennas and RF circuits concepts developed in XLIM laboratory and LabeX Sigma-Lim to offer an interesting trade-off between performances, energy consumption and overall complexity to address the problematic of beamforming in civil and mass-market applications. 5G and its future evolution is a great driver to develop such solutions. A reconfigurable antenna with a reduced number of RF excitations is presented, as well as RF frontend architecture used for a Ka-band demonstration. A main target of the work is to develop a system level simulation chain to optimize the interfaces between the elements of the antenna and front-ends. To this end, a powerful simulation platform, PREMISS, has been used to study and optimize a full-system.

A packaging solution based on densely packed carbon nanotubes bundles is described in this paper. A carbon nanotube based waveguide is considered and provide alternative approach for future high-performance embedded millimeterwave passive circuits and interconnects. A carbon nanotube equivalent bulk model is used for 3D electromagnetic simulations and parametric analysis.

Two RF packaging solutions are described in this paper. One is based on carbon nanotube fence-walls and contribute to a higher RF circuit integration, l0dB improvement in isolation is observed with the carbon nanotube fence-walls.; the other is based on carbon nanotube waveguide and provide alternative approach for EM shielded RF and millimeter interconnects. A carbon nanotube equivalent bulk model is used for 3D electromagnetic simulations and parametric analysis. The fabrication of the test structures are based on a low temperature carbon nanotube transfer technic. Experimental results validate the concept.

This paper present a recognition technique of metal placed inside and between two walls. A unique scheme of recognition of metallic objects through Ultra Wide Band (UWB) Modified Antipodal Vivaldi Antenna (MAVA) frequency range of (3.1GHz to 10.6 GHz) is presented in this paper.The working mechanism of detection system based on Time Domain Reflectrometry (TDR) using through wall imaging (TWMI). A very small duration pulses generated by Vector Network Analyzer (VNA) which are used for illuminate the wall.The analysis of a system under UWB antenna probe array. The simulation results of MAVA have given an enormous potential of penetration, in order to recognize concealed metal objects with fine precision, proving a smart development in the detection system technology. The improvement of resolution in an image, special filters have been developed and implemented. The design and optimization progression is conceded out via CST simulation software for parametric performance assessment of return loss, radiation pattern and directivity.

International audience; This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and for wireless communications applications. The objective is to develop a low cost ultra-sensitive sensor that can be integrated into a real time multi-sensing platform. The first demonstrators target the detection of harmful gases such as volatile organic compounds (VOCs) to monitor environmental pollution.

It has been recommended by the authors and Editor-in-Chief of the IEEE Transactions on Nanotechnology that this article will not be published in itsfinal form. It should not be considered for citation purposes; International audience; This paper presents the feasibility of a low-cost fully inkjet printed capacitive microwave flexible gas sensor based on a resonant electromagnetic transducer in micro-strip technology with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate and multi wall carbon nanotubes (PEDOT:PSS-MWCNTs) as sensitive material for Volatile Organic Compounds (VOCs) detection. The design and simulation results of the device on paper substrate for differential measurements are first described. This theoretical study based on both analytical and Finite Element Model approaches, validates the operating principle. The fabrication process and experimental devices are then presented, as well as electrical characterization results, both in air and under selected vapor analytes. These experimental results show the good sensor repeatability and sensitivity according to the transmission S parameter resonant frequency shift equal to -2.153 kHz/ppm and -1.855 kHz/ppm for ethanol and toluene vapor concentrations from 500 to 1300 ppm, respectively. This leads to conclude on promising future of such passive sensors and further integration into real-time multi-sensing platform adaptable for the Internet of Things (IoT)

Here, a new Faraday's cage using carbon nanotubes (CNTs) for radio frequency isolation is demonstrated. Densely packed CNTs were implemented on a guard ring structure. An antenna acts as a radiative source, while a receiving probe placed inside a CNT enclosure was used to measure the received signal. A total of 5-10 dB improvement in isolation was observed with the CNT enclosure, similar to what was obtained in an equivalent test structure with an aluminum enclosure. Such CNT isolation scheme could be implemented in densely packed three-dimensional circuits and packages, suitable for compact and light weight radar applications. EDB (Economic Devt. Board, S’pore)

International audience; This paper presents a chemical microwave flexible sensor based on a resonant electromagnetic transducer in micro-strip technology with poly (3,4-ethylenedioxythiophene) polystyrene sulfonate – multi wall carbon nanotubes (PEDOT:PSS-MWCNTs) as sensitive material for Volatile Organic Compounds (VOCs) detection. The results show a high sensitivity to ethanol and toluene vapors on the S parameters of a passive resonator over a large frequency range. It is equal to -1.59 kHz/ppm and -1.45 kHz/ppm for ethanol and toluene vapors respectively. This kind of sensor can be integrated into real-time multi-sensing platform adaptable for the Internet of Things (IoT).

International audience; In the areas of safety, health and environment, the detection of chemical compounds, VOCs and toxic gases, is a major societal concern. The explosion in recent years in the telecommunications market has led to the emergence of concept of sensor network. This new concept of communicating objects meets the growing need to deploy sensors for monitoring and analysing distributed applications. These systems rely on an architecture built around wireless autonomous sensors composed of nanostructured materials that are very effective in terms of sorption of chemical compounds, and of new low cost communication electronic devices printed on flexible substrates. Thus, the research effort requires a multidisciplinary approach around the engineering of new materials, transduction mechanisms and electromagnetic waves (microwaves).The CAMUS (CArbon & Microwaves-based Ultrasensitive Gas Sensors) project is proposed by a consortium of four labs with complementary skills: IMS Bordeaux UMR 5218, XLIM Limoges UMR 7252, IEMN Lille UMR 8510, CINTRA Singapore UMI 3288 CNRS-NTU-Thales.In this project, we propose the realization of a platform for microwave transduction associated with nanostructured materials, graphene and carbon nanotubes (CNTs), allowing the extraction of interference properties of conductivity and dielectric permittivity caused by the interaction of these materials with the target species. Thus, our approach aims to demonstrate the feasibility of a passive microwave resonator on a flexible substrate dedicated to the detection of chemical compounds in the vapor state.

This paper presents different metal deposition techniques used for the metallization of additively manufactured plastic components. Comparison between them are presented with a focus on their use with 3D printed Ka band bandpass filters. The results, in terms of conductivity, roughness and thickness, will be analyzed and measured up to 66 GHz by a resonant cavity method. The characterized metallization techniques will be applied on different 6th order bandpass filters working around 19 GHz.

This paper deals with a study on multiplexer topology based on 3dB couplers. A diplexer in Ku-band was conceived and printed using material jetting (Polyjet®) and Fused Deposition Modeling (FDM) technologies for this purpose. The different parts composing the diplexer are separately tested. In a first step, 3 dB directional couplers are printed with both technologies experimentally confirming the expected behavior. 4th order printed TE101 mode filters are tested as well, also providing sufficient performances (unloaded Q around 600) for the purpose of this paper. After assembling the different 3D printed parts composing this diplexer, the measured response confirms the reliability of the different manufacturing techniques and the robustness of this multiplexer technology.

This paper presents an inkjet printing capacitive microwave sensor for toxic vapor detection. The designed sensors were presented and fabricated with success. The experiments show sensitivity to ethanol vapor according to the S parameters. It is equal to 0.9 kHz/ppm and 1.3 kHz/ppm for the sensors based on 5 and 50 sensitive layers respectively. This sensor will be integrated into real-time multi-sensing platforms adaptable for the Internet of Things (IoT).

International audience; This communication presents results on the feasibility of an inkjet printed chemical gas sensor suitable for a real time multi-sensing platform. The prototype targets volatile organic compounds (VOCs) such as ethanol vapor to monitor environmental pollution. The designed and ink-jet printed microwave sensor is presented. Preliminary results have shown the influence of ethanol vapor on the electrical properties of the sensor at microwave frequency range. The sensor's sensitivity to ethanol vapor has been estimated to-2.48 kHz/ppm. The final aim of this work is to develop a low cost sensor for Internet of Things (IoT) applications.

This work presents a compact LTCC Alter hybridizing 2 resonator technologies (microstrip lines and SIW resonators). This solution makes it possible to find a compromise in terms of footprint and performance (insertion loss and flatness). The structure was synthesized and designed using an electromagnetic simulator.

This paper presents a continuously tunable bandpass filter fully made by plastic additive manufacturing. This filter is designed to provide a constant absolute bandwidth around 5.7 GHz using a mechanical movement. A 3D spiral ribbon made of metallized plastic is designed to create a 4th order Chebyshev bandpass filter by making it rotate in a standard WR159 waveguide. The obtained filter experimentally provides a 325 MHz +/− 35 MHz bandwidth while having its operating frequency be continuously tuned from 5.45 to 5.64 GHz (7.47% tuning range). The return loss remains better than 10 dB over the whole tuning range. Even if the insertion loss are rather high (1.6 to 3.6 dB) mainly due to the low conductivity used for the plating of the plastic parts, this proof concept demonstrates the validity of such design and of the use of additive manufacturing for prototyping new concepts of tunable waveguide filters.

This paper focuses on the improvement of chip to chip wireless interconnect developed previously by C. Brun and al. [11]. A 200 GHz coplanar waveguide (CPW)-fed carbon nanotube (CNT) array antenna have been developed. The simulated array antenna shows a −2dB gain in the main direction. An improvement compared to the −5 dB gain shown by a single antenna.

In the future, electronics will face many challenges beyond the prediction of Moore’s law. In this context, nanopackaging will play a crucial role for enabling future electronics to be consistent with future component, system, and circuit board (or global-level) requirements. Moreover, assembly approaches are moving toward heterogeneous three-dimensional integrated circuits (3D ICs) with silicon via wafer thinning, bonding technologies, and 3D system integration and miniaturization. Many of these packaging and assembly requirements are triggering an unprecedented pace of innovation in terms of new technologies, new system integration techniques, and new materials. Intensive research investigations are focused on carbon nanotubes (CNTs), graphene, 2D materials, nanowires, nanoparticles, and so on. In addition, many challenges remain to be faced with regard to the development of state-of-the-art interconnect interfaces, the development of predictive modeling tools based on multidisciplinary and advanced multiscales approaches, and the fabrication and tests of representative demonstrators with a significant impact.

Proofs of concept of CNTs based RF nanopackaging of mm wave circuits are presented in this review paper. Dedicated theoretical design tools based on EM simulations and equivalent models are described and validated. Theoretical results are presented and commented.