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A new electron cyclotron emission imaging antenna was designed and installed outside the torus on LHD. To improve the signal quality, we developed a local oscillator integrated antenna array (LIA), in which each channel has an internal local oscillation supply from a frequency-multiplier-integrated circuit. The labyrinth structure of the optical system comprises five mirrors to protect the LIA from plasma neutron emission. The initial results were obtained from the 2017 LHD experimental campaign. The MHD fluctuations and their fluctuation profiles were observed., source:https://doi.org/10.1585/pfr.13.3402063, identifier:0000-0002-8626-129X

In this manuscript, we experimentally demonstrate a parity-time-symmetric optoelectronic oscillator (OEO) with polarization multiplexed channels. We obtained a microwave single-mode oscillation at 9.5 GHz with phase noise values of -116.2 and -122.3 dBc Hz(-1) at 10 kHz offset frequencies, and side mode suppression values below -68 and -75 dBc Hz(-1), by utilizing a 1 km long and 5 km long single mode fiber delay lines, respectively. Our experimental results suggest that parity-time-symmetric OEOs with polarization multiplexed channels are simple and cost-efficient alternatives to their more complex counterparts., Turkish Academy of Sciences (TUBA); Scientific and Technological Research Council of Turkey (TUBITAK) [119F265], This work is partially supported by the Turkish Academy of Sciences (TUBA) and the Scientific and Technological Research Council of Turkey (TUBITAK) under the Grant No. 119F265.

In this manuscript, we experimentally demonstrate a parity-time-symmetric optoelectronic oscillator (OEO) with polarization multiplexed channels. We obtained a microwave single-mode oscillation at 9.5 GHz with phase noise values of -116.2 and -122.3 dBc Hz(-1) at 10 kHz offset frequencies, and side mode suppression values below -68 and -75 dBc Hz(-1), by utilizing a 1 km long and 5 km long single mode fiber delay lines, respectively. Our experimental results suggest that parity-time-symmetric OEOs with polarization multiplexed channels are simple and cost-efficient alternatives to their more complex counterparts., Turkish Academy of Sciences (TUBA); Scientific and Technological Research Council of Turkey (TUBITAK) [119F265], This work is partially supported by the Turkish Academy of Sciences (TUBA) and the Scientific and Technological Research Council of Turkey (TUBITAK) under the Grant No. 119F265.

The tri-agency Integrated Program Office (IPO) continues to manage the development, acquisition, and execution of the National Polar-orbiting Operational Environmental Satellite System (NPOESS). As directed by its acquisition decision authority in 2006, the NPOESS Program restructured its acquisition baseline with an emphasis on reducing complexity and ensuring continuity of observations presently delivered by the two operational systems NPOESS will replace - the Polarorbiting Operational Environmental Satellite (POES) and the Defense Meteorological Satellite Program (DMSP). Ocean observations continue to comprise nearly one-fourth of the 38 user-validated data requirements levied on the system and are drivers of the design and implementation strategy for two principal sensors: the Visible Infrared Imager Radiometer Suite (VIIRS) and the Microwave Imager-Sounder (MIS). The NPOESS Preparatory Project (NPP) will deliver a subset of these NPOESS ocean observations for demonstration and risk reduction after its planned launch in 2010. Recent performance assessments indicate that the restructured NPOESS will continue to deliver improved operational capabilities and satisfy the critical civil and national security needs for space-based ocean observations., Prepared in collaboration with the Integrated Program Office, National Oceanic and Atmospheric Administration, Silver Spring, MD. Presented at the MTS/IEEE Oceans 2008 Conference, Ocean, Poles and Climate: Technological Challenges, in Quebec City, Canada on 15-18 Sep 2008 and published in proceedings of the same. ISBN 978-1-4244-2620-1/08. See also ADM002176. The original document contains color images.

The purpose of this thesis is to explore the emerging possibilities of processing radiofrequency (RF) or microwave signals in optical domain, which will be a key technology to implement next-generation mobile communication systems and future optical networks. Research activities include design and modelling of novel photonic architectures for processing and filtering of RF, microwave and millimeter wave signals of the above mentioned applications. Investigations especially focus on two basic functions and critical requirements in advanced RF systems, namely: • Interference mitigation and high Q tunable filters. • Arbitrary filter transfer function generation. The thesis begins with a review on several state-of-the-art architectures of in-fiber RF signal processing and related key optical technologies. The unique capabilities offered by in-fiber RF signal processors for processing ultra wide-band, high-frequency signals directly in optical domain make them attractive options for applications in optical networks and wide-band microwave signal processing. However, the principal drawbacks which have been demonstrated so far in the in-fiber RF signal processors arc their inflexible or expensive schemes to set tap weights and time delay. Laser coherence effects also limit sampling frequency and introduce additional phase-induced intensity noise.

The field of optics-microwave covered by this 2 day lecture series can generally be defined as the study of high speed devices and systems operating at microwave, millimeterwave and even THz frequencies. The benefits drawn by the introduction of optics in microwave techniques are illustrated through numerous examples. This two-day lecture series covers the main applications of optomicrowaves to the defence area through a broad approach going from devices to systems., Text in English. Summaries in English and French. The original document contains color images. ISBN 92-837-1094-0. Presented at RTO SET Lecture Series held in Jouy en Josas, France on 2-3 Sep 2002; in Duisburg, Germany on 5-6 Sep 2002; and in Budapest, Hungary on 9-10 Sep 2002. For individual articles, see ADP014029 thru ADP014039

The availability of optoelectronic components operating up to 20 GHz brings attractive perspectives for optical processing of microwave signals. Furtherinore optically carried microwave signals can experience large time delays, especially in fiber based systems, providing time-frequency products in the range between 100 and 1000. Owing to their inherent parallel processing capabilities, optoelectronic architectures are well suited for the implementation in radar and electronic warfare systems of basic functions such as spectrum and time delay analysis, adaptive and progranunable filtering, correlation and waveform generation., Text in English. Summaries in English and French. The original document contains color images. ISBN 92-837-1094-0. Presented at RTO SET Lecture Series held in Jouy en Josas, France on 2-3 Sep 2002; in Duisburg, Germany on 5-6 Sep 2002; and in Budapest, Hungary on 9-10 Sep 2002, p5B-1/5B-12. This article is from ADA415644 Optics Microwave Interactions (Interactions entre optique et micro-ondes)

Microwave photonics has come of age and there are a number of military applications that could directly benefit from. Optically controlled phased array antenna is one of the most widely pursued applications. The fiber optic links are employed for distribution of a variety of communication, intelligence, tracking, radar signals. There are a number of issues that dictate the type of architecture that is employed for effective and reliable control of phased array. However, the most important benefit is in the optical signal processing of microwave signals. Fiber delay lines are an important element of an signal processing solutions., Text in English. Summaries in English and French. The original document contains color images. ISBN 92-837-1094-0. Presented at RTO SET Lecture Series held in Jouy en Josas, France on 2-3 Sep 2002; in Duisburg, Germany on 5-6 Sep 2002; and in Budapest, Hungary on 9-10 Sep 2002, p1-1/1-17. This article is from ADA415644 Optics Microwave Interactions (Interactions entre optique et micro-ondes)

The field of optics-microwave interactions can generally be defined as the study of high-speed photonic devices operating at microwave, millimeter wave or even THz frequencies and their use in microwave or photonic systems. In this multidisciplinary field at the interface between microwave techniques, ultrafast electronics and photonic technologies, typical investigations include, for example, high-speed and microwave signal generation, processing and conversion as well as the distribution and transmission of microwave signals via broadband optical links. From pioneering experiments in the 70's, this field of microwave photonics has paved the way for an enabling novel technology with a number of innovative and commercially important applications. This paper is intended to give an overview on this multidisciplinary field of microwave and millimeterwave photonics addressing specifically high speed optoelectronic components and their integration technologies and giving a glance on a few key microwave applications., Text in English. Summaries in English and French. The original document contains color images. ISBN 92-837-1094-0. Presented at RTO SET Lecture Series held in Jouy en Josas, France on 2-3 Sep 2002; in Duisburg, Germany on 5-6 Sep 2002; and in Budapest, Hungary on 9-10 Sep 2002, 2-1/2-18. This article is from ADA415644 Optics Microwave Interactions (Interactions entre optique et micro-ondes)

The bias-dependence of microwave-FET intrinsic noise sources in their hybrid configuration is theoretically determined, using a new quasi-2D (Q-2D) physical model based on Thornber's current equation [8]. It is shown that the correlation coefficient cannot be neglected, in agreement with empirical work in the literature. Experimental verification using noise-parameter measurements up to 26 GHz is presented., Peer Reviewed

Work carried out under this grant is summarized. In particular, the prediction of a novel ferroelectric material NaCaF3 is described and its predicted properties summarized. First principles calculations on a wide range of ionic molecular solids are summarized. These range from studies on halide perovoskites to work on alkaline earth silicates. In most cases very reasonable accord with experiment is achieved. One notable exception is the class of alkali cyanides which clearly require more sophisticated treatment. The basic theoretical approach is a combination of a Gordon-Kim modified electron gas theory with the quantum chemistry GAUSSIAN code to handle covalently bonded molecular ions. As indicated, this parameter free treatment reproduces experimental phase diagrams with good accuracy.

Wong Chi Sang., "August 2002.", Thesis (Ph.D.)--Chinese University of Hong Kong, 2002., Includes bibliographical references., Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web., Mode of access: World Wide Web., s in English and Chinese., http://library.cuhk.edu.hk/record=b6073501, Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/)

This is a technique using a fiber-optic, wideband array antenna beamformer having cascaded, chirped fiber gratings in a distributed architecture based upon the use of cascaded, fiber-optic, chirped Bragg gratings in a distributed architecture for use in wideband, time-steered array antennas. A wavelength tunable laser serves as a carrier for a microwave signal which is modulated upon it. The signal is corporately distributed to each feed of the array. Each feed then traverses a multi-port optical circulator and is reflected off a number of identical, chirped fiber gratings proportional to their position within the array. The signal is then demodulated and fed to the appropriate antenna element. All gratings are identical with the same length and dispersion (ps/nm). Time-steering is accomplished by tuning the laser wavelength such that the effective reflection point in an individual grating is changed due to the chirped nature of the grating.

An algorithm used to composite SSM/I 85.5 GHz imagery and derive sea ice motion was adapted for operational testing at Fleet Numerical Meteorology and Oceanography Command (FNMOC). A feature tracking technique was applied to a 6-month period, with data provided by FNMOC and the Naval Research Laboratory (NRL). Ice motions are detectable using the SSM/I motion algorithm, and fields of SSM/I motion vectors are qualitatively consistent with coincident fields of in situ buoy motion vectors. Accuracy of the SSM/I motion vectors relative to buoy motion vectors increase significantly with buoy speed. No correlation between SSM/I and buoy motion vectors is observed for speeds below 3 cm/s and correlation increases significantly above 5 cm/s. The results are very sensitive to compositing techniques used to combine SSM/I passes into a single sea ice representation. FNMOC data was composited using a "drop-in-the-bucket" technique while NRL data was composited by a bilinear interpolation technique. Significantly poorer results were found with ENMOC composited data.

During the period of this contract, the research program, "Non-linear microwave and fast optics studies of YBCO superconducting films" focused on several projects central to the program objectives. The main focus was on a collaborative study of the nonlinear microwave properties of superconducting YBCO, for which the research was carried out with collaborators at the Air Force Research Laboratory at Hanscom Air Force Base and the MIT Lincoln Laboratory. The research work included studies of; (1) the effect of the angular dependence of grain boundaries on the linear and non-linear microwave impedance of YBCO, (2) an extension of the coupled grain model to account for the distributed properties of junctions that are much longer than the London penetration depth, and have a distribution of the critical current densities and the normal state resistivities along the junction length, (3) second harmonic generation by Josephson junctions, (4) the effect of patterning on the surface impedance of YBCO thin films, and (5) the use of fast optics to investigate the basic interaction responsible for the high T(c) superconducting state in the BCS alkali metal-doped fullerene superconductors of K3C60 and Rb3C60. During this period one graduate student completed his M.S. thesis and three students completed Ph.D. theses.

To develop a methodology for remotely measuring the spatial and temporal variability of the atmospheric surface latent and sensible heat fluxes over the Labrador Sea using passive microwave imagery (SSM/I)., See also ADM002252.

The wideband, low loss transmission capability of optical systems has led to considerable interest in their use for distributing and controlling microwave signals in applications such as antenna remoting, wideband cable television distribution, optically controlled phased arrays and microwave signal processing. The use of microwave sub-carrier multiplexing on dark fiber systems also may be of importance in the near future, and to realize multi-gigabit optical communication systems, microwave design techniques must be used. The International Topical Meeting on Microwave Photonics is intended to present recent advances in the multi-disciplinary research area, ranging from novel devices to systems deployed in the field.

This research has been aimed at investigating new means of microwave and millimeter wave generation using a nonlinear optical waveguide structure. Research has focused on the approach of using a single Ti-sapphire laser to produe separate beams which are shifted slightly in frequency by the use of very narrow bandpass filters.

Millimeter wave circuits require studies of wave interactions from electromagnetic point of view in the analysis, design and characterizations of circuits, components and systems. In this research, wave interaction issues are central in a number of investigations. The topics studied include active quasi-optical structures for power generation, active integrated antennas for radar, communication and transponders, optical control of remotely located active antennas, and comprehensive electromagnetic simulation of active microwave and millimeter wave circuit structures. We have accomplished milestones in these subjects. Quasi-optical power combiner has an excellent capability while the electromagnetic simulation enhance the capability of obtaining much more information content than in conventional CAD programs on the physical and dynamic behavior of the circuits.

A multiband microwave polarimetric scanning radiometer (PSR) has been constructed for airborne observations from the NASA DC-8 airborne platform. The primary application of the PSR is the development of optimal spaceborne bard ware configurations and retrieval algorithms for passive wind. vector sensing over the ocean surface. Four radiometers, operating at 10.7, 18.7, 37, and 89 GHz, each measure the first three modified Stokes' parameters (T(sub upsilon), T(sub h), and T(sub u). A gimbaled mechanism allows observations at any incident angle within a cone of 700 half angle around nadir. The PSR's four radiometers and two axis scanning capability will provide unique polarimetric data for microwave emission studies of both ocean and land surfaces, as well as atmospheric clouds and precipitation.

We have demonstrated a tapped delay line microwave filter based on the use of high dispersion fiber as the tunable time delay. This system offers advantages of high bandwidth and tunability over current methods of time delay filtering. The method uses a single length of high dispersion fiber to achieve a variable time delay. By tuning the wavelength the relative time delay is changed. For a 1 km length of high dispersion fiber (-98 ps/km-nm) approximately 5ns of delay has been demonstrated over a 50 nm tuning range.

The principal objective of this project is to investigate problems associated with achieving the drive/read-out system complexity necessary to control a phased array antenna with optical heterodyne techniques. In particular, this work has concentrated on multi-channel microwave optical conversion. The approach has been to study the problems associated with device arrays of single sideband modulators that would be necessary to control the amplitudes and phases of all signals delivered to a phased array front end. The incorporation of our available in-house developed tools into that of already existing tools (such as MDS-Microwave Design Software) has been undertaken to design a single side-band modulator (SSBM). It was found that MESFET oscillators and the associated control lasers can be modeled by simply changing a constant in the model to give their characteristics with and with out optical injection. This is useful for injection locking of active antennas for accurate and efficient phased array antenna design. (AN)

Many potential applications exist for high resolution radar such as direction finding, high accuracy tracking, target counting, and high resolution radar imaging. All of these applications require the use of large, thinned, random or periodic antenna arrays. Many uncertainties exist in such large antenna systems. For example, exact element positions are generally not known because of surveying problems or flexing of the large antenna structure. Adaptive beamforming (ABF) is the solution to the unusual design that achieves these objectives. It deduces the errors in the locations of the receivers that are distributed around the airport or on the air frame and automatically compensates for them in the image processing. This year's work concentrated on three tasks. The first was to develop a generalized ABF theory for the class of spatial correlation algorithms. The second was to extend thc resolution of a microwave imaging radar to 15 cm, and the third was to study enhanced target detection sensitivity and target recognition. (MM)

High Temperature Superconductor (HTS) devices can and will improve the performance of ESM and shared aperture receiver systems. For the near term the most promising candidate for the reference Channelized Cued ESM receiver system is an HTS IF Delsy line that can provide 200 nanoseconds of delay across a 3 to 5 GHz band. Such a delay line can improve sensitivity by 1 to 2 dB while providing about a 6 dB improvement in two tone dynamic range. Perhaps even of greater importance is that the low device loss combined with the elimination of multiple amplifiers previously needed to overcome loss can significantly improve the amplitude and phase tracking of the delay lines. In future systems it is unlikely that a single HTS device will be employed. Rather, it is more likely that large portions of the RF architecture will be placed in a cooler as a means of achieving performance and cost advantages. This is thought to include an HTS front-end, conventional IF amplifier, and HTS IF receivers. Looking even further in the future it is likely that entire HTS receivers will be remotely located with their HTS antennas and only digits will be returned to central for processing.

The symposium's objective is to provide a forum for exchanging information on the latest developments in microwave remote sensing. The decade of the 1990s promises to be an exciting era for microwave remote sensing. We feel that an excellent technical program has been assembled, featuring many aspects of microwave remote sensing including a special session on ERS-1. (MM)

Because tropical cyclones have deep warm cores they are amenable to monitoring using passive microwave radiometers in the 55 GHz (Oxygen) band. However, such radiometers currently have horizontal resolution of 100 km or more, which is significantly larger than the eye of most tropical cyclones. The warm anomaly directly observable in the brightness temperature distribution is therefore an underestimate of the actual warm anomaly strength. The subject of this contract is an algorithm to correct for this underestimate. Passive microwave observations are modeled as an interaction between the radiometer antenna pattern and an analytic function approximating the thermal structure of a tropical cyclone. Solution of the inverse of this model using a maximum likelihood method yields an estimate of the amplitude of the warm anomaly. Application of this technique to observations from two different radiometers (MSU and SSM/T) indicates that it is relatively successful at correcting for horizontal resolution differences. However, the warm anomalies so obtained are little better than the raw observations themselves as estimators of tropical cyclone intensity. Reasons for this are examined and some potential avenues of research are suggested. (MM)

The purpose of this research has been to observe and analyze the structural details and intensity evolution of Super Typhoon Flo (1990) using SSM/I data. Flo's structural characteristics were observed with SSM/I imagery and then compared with conventional, infrared and visible satellite data to illustrate qualitative distinctions between the two types of data. High resolution 85-0hz imagery showed more convective detail than operational line scan (OLS) data while low resolution 19-0hz data afforded more realistic analysis of the active tropical cyclone region when compared with 0MS data. Center locations determined in horizontally polarized 85-0hz imagery offered improvement over the OLS fixes obtained from corresponding DMSP passes. However, the SSM/I derived 85 and 19-0hz retrieval statistics, employed as intensity indicators in previous tropical cyclone research, were poorly correlated with changes in Flo' 5 intensity. Two over ocean SSM/I rainfall rate retrieval algorithms were compared for accuracy. The more accurate algorithm employing the 85-0hz frequency was used to characterize Super Typhoon Flo's rainfall rate distribution and intensity evolution. Results are generally similar to previous studies. Maximum rainfall rates were usually confined to the eyewall and inner-core region. Furthermore, changes in Flo's average inner-core rainfall rate correlated reasonably well with intensity changes. (MM)

Optical injection of MESFETs directly affects the operating characteristics of the devices. The MESFET properties, induced by optical injection, can stabilize oscillator operating frequency, control amplifier gain, and open the door for feasible integrated microwave-optical devices. The optical injection of DC MESFETs, oscillators, and amplifiers is explored. Systems applications, including phased array radar, wave division multiplexing (WDM) and computer clock control, are provided. The main contributions of this research are analyzing the modulation properties of the locked laser subsystem, using the locked laser system to inject MESFET devices and characterizing the photo-effects in MESFET circuits, reducing the phase noise in a microwave oscillator via optical injection and developing a theoretical description of the injection properties of oscillators that can be used to describe an injection locked laser and a microwave oscillator with a change of constants.

The main principal of this microwave multiband phased array antenna is the use of optically controlled photonic delay line for beam forming and steering. This system is suitable for spaceborne and airborne phased array applications. it also has a potential to perform frequency hopping of transmitting signals since it is a dual band transmitter (L and X-band) and the dual band system is controlled by one set of frequency independent delay lines. The L-band (1 to 2.6 GHz) array and the X-band (8 to 12 HGz) array, each has the same physical length. Each is split into four subarrays and use a common time delay generator for each subarray on both bands. True time delay with wideband radiating elements permits large transmit and receive frequency excursions without beam wander (beam squint) as the frequency is changed, and also permits the use of wideband waveforms. The advantage also extends to both communications and surveillance applications where the beam wanders off target could occur without the use of the optically controlled true time delay beam forming and steering.

The principal objective of this project is to investigate problems associated with achieving the drive/read-out system complexity necessary to control a phased array antenna with optical heterodyne techniques. The approach has been to study the problems associated with device arrays of single sideband modulators that would be necessary to control the amplitudes and phases of all signals delivered to a phased array front end. However, recent results of closely related research, when combined with results for this project, have led to a new viewpoint of the problem. it appears that a greater degree of complexity of control can be achieved by modulating a small number of optical channels and locking them to previously self-locked array of active radiating elements. This approach promises to lead to a better system solution as well as a technical study which uncovers many new interesting problems in the computer aided analysis of nonlinear electromagnetic systems

A process for making thick metal structures on a substrate has the steps of: selectively exposing a thick layer of photoresist disposed on a substrate to ultraviolet radiation including the 350 nm to 450 nm portion of the spectrum of a mercury vapor lamp, where the photoresist layer is a heat-treated and hydrated photoresist layer, to fully pattern the substrate; developing the patterned substrate by contacting the photoresist layer with a photoresist developing solution; exposing the photoresist layer to a plasma for hardening the pattern against thermal flow; hardbaking the photoresist pattern on the substrate; plating the metal onto the patterned substrate using a low current density (J) during at least part of the plating process, making a thick metal structure on the substrate.

This publication is the 20th edition of the annual Arctic sea-ice atlases prepared by the JIC. The atlas contains weekly charts depicting Northern Hemisphere ice conditions and extent. The significant use of high resolution satellite imagery, combined with valuable ice reconnaissance data from various sources, has greatly improved the accuracy of these analyses. The purpose of this atlas is to provide the user with reliable weekly hemispheric ice analyses. These charts are prepared by experienced Navy and NOAA ice analysts, who plot and evaluate numerous data sources: (a) Conventional shore station, ship, and aerial reconnaissance observations; (b) Satellite data from various sensors. Table I, located on the inside back cover, lists these sensors and their availability. A final product is synthesized from the inputs described above. When insufficient data is available, estimated boundaries are plotted, using meteorological data and computer generated ice drift vectors to determine estimated ice position. (MM)

The Navy's Polar Ice Prediction System, which is run daily at the Fleet Numerical Oceanography Center (FNOC), is initialized once a week from ice concentration data derived by the Navy/National Oceanic and Atmospheric Administration Joint Ice Center. Ice concentration data, derived by applying the U.S. Navy's algorithm to the Defense Meteorological Satellite Program Special Sensor Microwave Imager (SSI) data, have been collected from FNOC on a daily basis and archived at the Naval Research Laboratory. These data were interpolated to the operational ice model grids for possible use as real-time daily update to the operational forecast systems. Collection of data with coverage from the Pole southward to 400 N latitude allows for the observation of ice concentrations for the entire Arctic region and surrounding coastal seas. SSM/I ice concentration data from 1992 are presented for each available day and on each of the operational model grids. Sea Ice Forecasting, Sea Ice Models, Sea Ice Analysis

This report summarizes the research activities carried out in Electromagnetics and Microwave Laboratory, Department of Electrical Engineering, Texas A and M University. The project was sponsored by the U.S. Army Research Office under contract No. DAALO389-K-0085. The topics of investigation included active antenna elements, spatial power combining and injection-locking, quasi- optical components, novel planar slotline and coplanar waveguide circuits, and other circuit developments and analyses. A list of publications and a report of invention are included. Quasi-Optical Techniques, Microwaves, Millimeter-Waves, Power Combining, Active Antennas.

The principal objective of this project is to determine the most efficient means of encoding a microwave/millimeter-wave signal from a patch antenna onto an optical carrier in an electro-optic substrate for subsequent optical processing of the microwave/millimeter-wave signal. Our approach during the last period has been to continue the development of design models that would relate the performance of integrated electro-optic devices to the fabrication. parameters used in making them. Our emphasis has been on the design and fabrication of coplanar waveguides for electro-optic devices. This includes the design of a coplanar waveguide coupler at 5 GHz. A new technique for analyzing discontinuities in coplanar waveguides was also developed.... Microwave optics, Phased array radar, Patch antennas, Single side band modulators, Modulators, Electro-optics.

The combining of optical and microwave technology is imminent, especially the integration of optical and microwave circuit functions on the same circuit or chip. Since the MESFET is the main active component of the GaAs MMIC, it makes sense to explore its properties as an optical detector for the detection of microwave and control signals in fiber optic links. This report is a review of the state of the art in the control of microwave devices and circuits by optical means. First, the use of the MESFET as the optical detector for the control of microwave circuits will be reviewed. Then, investigation for the optical control of microwave devices such as the Gunn device, impact ionization avalanche transit time device (IMPATT), high electron mobility transistor (HEMT), and bipolar transistor will be presented. Finally, different types of photodetectors are discussed and compared with the MESFET.

Improved velocity matching in LiNbO3 modulators has been achieved by several workers using a combination of relatively thick (greater than or = to 1 micrometer) S1O2 buffer layers and thick (typically greater than or = to 10 micrometers) plated electrodes. Utilizing this combination, microwave indices less than or = to 2.5 have been achieved. However, increase in electrode thickness lowers device impedance, which raises drive power requirements and causes mismatch to most common 50 omega sources. This decrease is partially compensated by the thicker buffer layer and by employing large gaps (typically 15 micrometers) between the hot and ground electrode(s), both of which maintain the impedance at a high value. They also increase the drive voltage, however, resulting in a larger voltage-length product relative to conventional modulators. To achieve closer velocity matching would require additional increases in electrode/buffer thicknesses, resulting in even higher voltages. Here we describe a device which also utilizes a thick electrode/buffer layer geometry. However, it also introduces two novel features, resulting in a device which achieves almost exact velocity matching to the optical index, maintains high impedance, and has a voltage-length product which is as good or better than previous devices of this type. In addition, it maintains this performance over the whole range of wavelengths from 1.3 to 1.55 micrometers. This latter property is very important for optical measurement applications such as network analysis and optical sampling., This Article is from 'Integrated Photonics Research'. Volume 10, AD-A255 423, p005-008.

The paper win explore the use of Optical Fiber Thermometry (OFT) in applications where coupling of microwave energy is the form of heating. These include sintering of ceramic materials, brazing, analytical work and other applications ranging from 200 deg C to 4000 deg C. OFT includes both contact and non-contact temperature measurement based on Aluminum Oxide (Sapphire) optical sensors. Proper methods of application, heat transfer solutions and expected results will be explored. Recent developments resulting in total immunity of the sensor technology to electromagnetic interference will be explained., This article is from 'Ceramic Transactions. Volume 21. Proceedings of the Symposium on Microwave Theory and Application in Materials Processing Annual Meeting of the American Ceramic Society (23rd) Held in Cincinnati, Ohio on April 29 - May 3, 1991,' AD-A253 631, p641-646.

A traveling wave (TW) photodetector with a coplanar stripline structure was and fabricated in semiinsulating GaAs. Ohmic Au/Ge/Ni contracts were formed by a thermal annealing process. Testing was accomplished using an optical delay line arrangement to achieve either matching or mismatching of the microwave phases of the optical inputs and the microwave output signal. For the phase-matched case, the optical inputs are coherently combined to produce the TW photodetector output. The observed average microwave output power over the frequency range 0.5-5 GHz was 11 dB greater for four identical inputs than for a single input. This compares with an idea value of 12 dB for the power increase. For the unmatched case, the TW photodetector operates as a transversal filter, with the fundamental frequency determined by the optical/microwave time-delay mismatch. Experimentally, a fundamental frequency of 4.3 GHz was observed for two, three or four optical inputs. The expected sidelobe pattern was seen in each case.

Partial contents include: (1) Water vapor and cloud water validation; (2) Wind speed validation; (3) Land parameter algorithm validation and calibration; (4) Sea ice validation; (5) Description of hac and complete aes/ york sea ice algorithms; (6) Precipitation validation; (7) Cloud amount validation; and (8) Geolocation.

This program has supported theoretical and experimental studies in several areas of device physics: the physics and applications of radiative collisional lasers, pair absorption pumped lasers, the use of microwave pumping for the excitation of excimer and other high pressure lasers, and the development of anti-Stokes spectroscopy for the study of core-excited atomic levels.

The purpose of this thesis was to analyze a collection of passive microwave sensor output and determine if a relationship existed between that output and soil moisture content. A second objective was to identify procedural errors which may have hindered the thorough analysis of the data set and propose potential solutions. In processing the data into a form which could be analyzed, a weighting technique was developed to help reduce the variability in the sensor readings caused by the large footprint size. This weighting technique used a Bessel function to represent the decrease in beam strength within a ground location were then weighted based on the ground sample position in the footprint. The study failed to show that any relationship exists between soil moisture and passive microwave response. The results, rather than being significant, are inconclusive. Many procedural and processing errors in the experiment, coupled with a lack of data on some important variables, left the analysis with only a small chance of success. However, these errors are identified and potential solutions for many of these errors are identified. The weighting technique showed a statistically insignificant increase in the relationship values, yet with additional study could prove to be an asset in this field. Keywords: Radiometry; Optical detection; Microwave optics; Space- based remote sensing; Soil mechanics; Optical data; Weighting functions; Surface truth; Thesis. (edc)

Pub. in Proceedings of the Society of Photo-Optical Instrumentation Engineers, v259 p115-124, 1-2 Oct 1980

This thesis provides a compendium of analytical techniques which can be used to calculate the fields that are created when an electromagnetic wave is incident upon a physical object. Quasi-optical techniques (Geometrical Theory of Diffraction and Uniform Theory of Diffraction) are analyzed along with the more classical physical and geometrical optics techniques (Kirchoff Diffraction Theorem, Sommerfeld Diffraction Theorem, Fourier optics, and geometrical optics). The approximations that are used in each technique along with the regions of the electromagnetic spectrum where each technique can be applied are emphasized. Each technique is derived and all are shown to be ultimately dependent upon the validity of Maxwell's equations. The Fourier optics and Geometric Theory of Diffraction techniques are shown to be direct mathematical extensions of the Sommerfeld Diffraction Theorem. Each technique is then applied to a simple example problem. The technique of Fourier optics is shown to be very powerful while remaining mathematically simple. The Fresnel and Fraunhoffer approximations are most readily understood when this technique is used. It is also shown that the Geometric Theory of Diffraction and Uniform Theory of Diffraction are capable of giving accurate results when the physical object has a complex geometry. Keywords include: Diffraction; Millimeter waves; and Microwave optics.

The primary objective of NORDA's Ka-band Radiometric Mapping System (KRMS) program is to provide basic research needed for Navy development of an operational imaging system that can produce detailed information concerning ice conditions over broad regions of the Arctic. To this end, methods suitable for automated identification and classification of sea ice types and open water are being developed. An experimental plan has been formulated that will lead to an automated system that will provide real-time ice classification information onboard Navy aircraft. This report represents completion of the initial state of this plan. During March 1983 extensive high-quality KRMS imagery and coincident high-resolution photography were obtained of ice in the Beaufort Sea. Analysis of these data suggests that four classes of winter surfaces can be distinguished solely on the basis on Ka-band brightness temperature: open water, frazil, old ice, and young/first year ice. New ice (excluding frazil) and nilas display brightness temperatures that overlap the range of temperatures characteristic of old ice and young/first year ice. Scenes in which new ice or nilas are present in appreciable amounts are subject to substantial errors in classification. Textural characteristics of nilas and new ice, however, differ significantly from textural features characteristic of other ice types and probably can be used with brightness temperature data to classify single-band microwave images., Original contains color plates; All DTIC and NTIS reproductions will be in black and white.

The results of an extensive characterization of microwave-optical devices is presented. The study has concentrated in the optical injection locking of IMPATT oscillators, high-speed analog modulation of (GaAl)As injection laser, mode-locking of (GaAl)As injection laser, and high-speed optical detectors.

This report describes an efficient numerical scheme developed for investigating secondary flows, and outlines the design of an experimental set-up for obtaining detail in channel three dimensional secondary flow measurements. The analysis applies to inviscid internal rotational flow fields and leads to a very efficient numerical scheme for predicting the secondary flow phenomena. The analysis is applied to the rotational flow in a 90 deg bend with rectangular cross-section and then compared with the experimental data. It is concluded from the comparison that the physics of the secondary flow problem are well represented in the analysis. The analysis can be adapted with some modifications to variable area ducts, and turbomachinery passages. (Author), See also report dated 28 Feb 79, AD-A065 696.

This report summarizes activity by the Radar Devision of the Naval Research Laboratory in support of the Microwave Landing System program in the time period May 1975 through September 1979. This technical support was primarily associated with the ground scanning antennas. Initial emphasis was on microwave optical scanning techniques. This phase of the effort resulted in significant innovative contributions, but the more pressing objectives of the program shifted to the analysis of problems associated with phased array antennas. The Naval Research Laboratory contributed to the study of phased array in several ways. Computer simulations of internal monitoring systems, which can locate failed components, were carried out. A performance simulation of a general phased array using digital phase shifters was written. The performance characteristics of digital phase shifters were measured and statistically analyzed. Several research contracts for promising phased array techniques were awarded to industrial contractors. In addition to research on the primary MLS functions, which involve scanning linear phased array antennas, NRL has studied the realization of a 360-degree scanning antenna utilizing a circular array. This report contains a nontechnical review of all activities, supported by technical appendices and a listing of reports and memoranda. (Author)

The line-source bootlace lens, produces optimum focusing characteristics when it is constrained to exhibit front-to-back as well as right-left symmetry. It is shown that the symmetric bootlace lens is a one-parameter family when the radiating array is specified to be lambda/2 spaced with + or - 90-degree coverage. Design equations for the lens are derived, and overall focusing performance and design data are plotted. A computer program of the design equations is presented.