Design and Performance Evaluation of a Time Domain Microwave Imaging System

We design a time domain microwave system dedicated to medical imaging. The measurement accuracy of the system, that is, signal-to-noise ratio, due to voltage noise and timing noise, is evaluated. Particularly, the effect of coupling media on the measurement accuracy is investigated both numerically and experimentally. The results suggest that the use of suitable coupling media betters the measurement accuracy in the frequency range of interest. A signal-to-noise ratio higher than 30 dB is achievable in the range of 500 MHz to 3 GHz when the effective sampling rate is 50 Gsa/s. It is also indicated that the effect of the timing jitter on the strongest received signal is comparable to that of the voltage noise

An ultrafast digitizer for continuous measurements from microwave fusion diagnostics

Fast digitizers are employed in a variety of experimental contexts, including for microwave measurements from fusion plasma diagnostics. However, most existing commercial digitizers used for this purpose are severely limited by their onboard memory. Here we present a system developed from mostly commercially available hardware components capable of acquiring essentially indefinitely (here ∼10 s) while meeting the target performance of 5 GHz analog bandwidth with a rate of 10 billion samples per second and 8 bits per sample. At its core is a field-programmable gate array (FPGA) receiving data from a high-performance analog-to-digital converter (ADC). The data are continuously streamed with a maximum throughput of 120 Gb/s from the FPGA to a computer over optical fiber in the form of raw Ethernet packets, allowing the use of entirely standard networking hardware in the PC. Whilst this technology is transferable to a range of applications, we are motivated by the demands of microwave scattering measurements, for which the new digitizer increased the acquisition duty cycle from 6% to 100%. In this paper we describe our digitization system, demonstrate its capability, and then use it to acquire data from microwave diagnostics at the ASDEX Upgrade and Wendelstein 7-X fusion experiments

Development of a Real-time Ultra-wideband See Through Wall Imaging Radar System

Ultra-Wideband (UWB) See-Through-Wall (STW) technology has emerged as a musthave enabling technology by both the military and commercial sectors. As a pioneer in this area, we have led the research in addressing many of the fundamental STW questions. This dissertation is to investigate and resolve a few hurdles in advancing this technology, and produce a realizable high performance STW platform system, which will aid the STW community to find the ultimate answer through experimental and theoretical work. The architectures of a realizable STW imaging system are thoroughly examined and studied. We present both a conceptual system based on RF instruments and a standalone real-time system based on custom design, which utilize reconfigurable design architecture and allows scaling down/up to a desired UWB operating frequency with little difficulty. The systems will serve as a high performance platform for STW study and other related UWB applications. Along the way to a complete STW system, we have developed a simplified transmission line model for wall characteristic prediction; we have developed a scalable synthetic aperture array including both the RF part and the switch control/synchronization part; we have proposed a cost-effective and efficient UWB data acquisition method for real-time STW application based on equivalent-time sampling method. The measurement results reported here include static image formation and tracking moveable targets behind the wall. Even though digital signal processing to generate radar images is not the focus of this research, simple methods for image formation have been implemented and results are very encouraging

Estudio de un sistema de medición de niveles de riesgo para zonas de desprendimientos a través de tecnología SDRadar en un ambiente de laboratorio.

Se realizó un estudio de un sistema de medición de niveles de riesgo para zonas de desprendimiento con tecnología SDRadar en un ambiente de laboratorio. Primero se realizó pruebas de simulación del funcionamiento de un radar en el software de Matlab, una vez comprendido su funcionamiento luego de varias simulaciones, se implementó el sistema de medición con dos tarjetas USRP B210 conectados a dos computadores respectivamente, una para la transmisión y otra para la recepción de la señal en cada uno se instaló una antena con una frecuencia de operación de 5GHz y ganancias de 10db, para incrementar la potencia del radar se usó dos amplificadoresZJL6G+ en cascada de 10db cada uno, lo que nos proporcionó una ganancia total de 20db mejorando significativamente la potencia del sistema, para la medición de tres materiales tierra, arena y macadán en diferentes grados de humedad(cero, leve1, leve2, leve3, moderado1, moderado2, moderado3 y fuerte) de los cuales se obtuvo sus índices de reflexión y con los mismos se calculó sus valores de permitividad relativa, relacionando de esta forma los valores de permitividad con la humedad. Después se analizó dos escenarios en riesgo de desprendimiento uno extremadamente seco y otro extremadamente húmedo y se determinó valores límites de riesgo para cada material .El sistema nos proporciona información muy valiosa para futuras investigaciones o implementaciones. Se recomienda usar la implementación propuesta.A study of a measuring system of risk levels was developed in detachments zones using SDRadar technology at a lab environment. The first step was the simulation testing of how a radar works into the Matlab software, once its operation was understood and after several simulations, the measuring system was implemented by connecting two USRP B210 cards to a couple of computers, one for broadcasting and the other for reception of the signal, then an antenna was installed in each devise with an operation frequency of 5GHz and an amelioration of 10db. For boosting the power of the radar, two ZJL6G+ amplifiers were used in cascade of 10db each, which made an improvement of 20db in the power system. To measure three materials such as soil, sand and macadam in different moisture degrees (zero, mild 1, mild 2, mild 3, moderate 1, moderate 2, moderate 3 and strong) at the obtained permittivity values, two scenarios of detachment risk were compared, one extremely dry and the other extremely wet, determining that there is a risk in 6 values. The system provides important information for future investigations or implementations, being the one proposed in this study the most recommendable

Design and application of microstrip leaky wave antennas for radar sensing

textThis dissertation investigates the application of the frequency-scanned beam of a microstrip leaky wave antenna (LWA) to track humans in the two-dimensional (2-D) range-azimuth plane. The history, operating principles and frequency-scanned properties of a microstrip LWA are first reviewed. The basic concept of using a microstrip LWA to track humans is verified by designing, building and testing a broadband microstrip LWA, developing the necessary processing algorithm, and collecting data using a vector network analyzer. A number of topics are then investigated to further advance the concept. First, the idea of combining the frequency-scanned antenna with a short-pulse ultra-wideband (UWB) radar is developed to realize a portable, real-time system for human tracking. The radar concept and the components of the system are discussed in detail. Line-of-sight and through-wall measurements of a human subject are carried out to demonstrate the performance. Second, a new LWA structure is proposed to achieve a narrower azimuth beam, which requires both a small leaky-wave attenuation constant and a long aperture. The transverse resonance method (TRM) is applied to analyze the proposed structure and the results are verified with measurements of a built prototype. Third, a new signal processing technique, compressive sensing, is applied to further improve the resolution in both the azimuth and down range dimensions. The technique is tested with simulation and measurement data and is shown to produce sharper target responses in both the down range and azimuth dimensions. Lastly, the radar cross-section (RCS) of a microstrip LWA is studied. The antenna mode scattering and structural mode scattering are modeled separately. A ray picture is provided to explain the observed time-domain features using the group delay of the leaky wave.Electrical and Computer Engineerin

Desarrollo de un algoritmo en matlab para la optimización de la resolución de una tarjeta USRP B210 para aplicaciones SDRadar.

El presente trabajo de titulación tuvo como objetivo principal desarrollar un algoritmo en matlab que permite optimizar la resolución de una tarjeta periférica universal de software de radio (USRP) B210, analizando las limitaciones y características de la misma para desarrollar aplicaciones de radar definido por software (SDR). En el desarrollo del algoritmo se utilizó un radar de onda continua modulada en frecuencia (FMCW) implementando una señal chirp, considerando que 25 MHz es el máximo ancho de banda que la tarjeta puede proporcionar dando como resultado una resolución de 6 metros. El método utilizado que optimizó la resolución de la tarjeta fue el de transmitir un determinado número de señales con distintos anchos de banda dando como resultado una resolución diferente, detectando y almacenando el objetivo en una matriz. Se estableció que con 14 mediciones a un espacio de ancho de banda de 0.5 MHz entre cada señal, es lo más óptimo para mejorar la resolución de la tarjeta. Considerando las limitaciones que el algoritmo presenta, como la determinación de dos zonas con un número de muestras de 94 objetivos de 6 a 100 metros: donde la primera zona está limitada por un error de medición de e<1m, en la segunda zona con un error de medición 1m<=e<2m con 69,15% y 30,85% de objetivos detectados respectivamente, determinando así su efectividad y confiabilidad. Se recomienda emplear el algoritmo en aplicaciones SDR como detección de objetivos, aplicaciones topográficas o en un radar de apertura sintética (SAR).The main objective of the present work was to develop a MATLAB algorithm that allows the optimization of the resolution of a Universal software radio peripheral (USRP) B210, analyzing the limitations and characteristics of it to develop software defined radar applications (SDR). In the development of the algorithm was implemented a frequency modulated continuous wave (FMCW) radar by implementing a chirp signal, considering that 25 MHz is the maximum bandwidth the card can provide resulting in a resolution of a 6 meters. The method used to optimize the resolution of the card is to transmit a certain number of signals with different bandwidth resulting in a different resolution, detecting and storing the target in a matrix. It was established that with 14 measurements al a bandwidth space of a 0.5 MHz between each signal, it is the most optimal to improve the resolution of the card. Considering the limitations that the algorithm presents, such as the determination of two zones with a number of samples of 94 targets from 6 to 100 meters: where the first zone is limited by a measurements error of e<1 m, in the second zone with a measurements error 1m<=e<2m with 69,15% and 30,85% of objectives detected respectively, thus determining its effectiveness and reliability. From the results obtained it is recommended to use the algorithm in SDR applications such as objective detection, topographic applications or in a synthetic aperture radar (SAR)

Development of a digital demodulator and a simulation environment for a telemetry system

Orientador: Luís Geraldo Pedroso MeloniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de ComputaçãoResumo: Esta dissertação apresenta os resultados obtidos com a pesquisa e implementação de um sistema de demodulação para o receptor de rastreio de um radar de telemedidas. Um radar de telemedidas é responsável pela identificação de um conjunto de medidas realizadas no objeto espacial e enviadas para a antena através de um transponder. A antena de telemedidas deve rastrear o objeto, mantendo-se sempre apontada na direção deste. Para realizar esta função foi utilizada a técnica de monopulso de um canal. Na técnica de monopulso de um canal, cabe ao demodulador digital do receptor executar uma identificação de envoltória e uma demultiplexação temporal que deve permitir encontrar os valores angulares dos erros. A implementação resultou em uma placa de demodulador digital, realizada com um Field Programmable Gate Array (FPGA) da família Cyclone II, e um controlador Freescale, embarcados em uma Placa de Circuito Impresso (PCI) de quatro camadas, projetada para interfacear sinais digitais para controle do sistema de telemedidas e para condicionar os sinais analógicos para posterior processamento. Além de ter interface com placas específicas (por exemplo, CAF - Controle automático de freqüência, CAG - controle automático de ganho, Gerador de Teste, etc), possui também uma interface Controller Area Network (CAN) para comunicação com os módulos de controle de servomecanismos da antena e de interface usuário. Foi desenvolvido também um ambiente de simulação para o demodulador digital em Matlab permitindo verificar a coerência com os resultados esperados e traçar cenários de testesAbstract: This project presents the results obtained by the research and development of a Demodulation System for a telemetry radar tracking receiver. A telemetry radar system is responsible for identifying a set of measures taken from a spatial artifact and is transmitted by a transponder to its antenna. The telemetry antenna must track the spatial object, maintaining the antenna pointing in the correct direction. To execute this function a single channel monopulse technique is applied. Since the single channel monopulse technique is used, a digital demodulator task is then run for amplitude identification and the de-multiplexing time frame must occur in order to calculate the angle values of errors. This process is explained during the dissertation after the presentation of the main characteristics of radars and some aspects of telemetry systems. The solution is a digital demodulator electronic board, build with an FPGA (Field Programmable Gate Array) from Altera Cyclone II® family, and a Freescale® controller, over a multilayer PCB (Printed Circuit Board) projected to interface with digital signals for the Telemetry Control System and to conditioning analogical signals for processing tasks. The developed board has the CAN (Controller Area Network) interface to communicate with the servomechanism control modules associated with the Antenna and is placed in an armored drawer - to avoid electromagnetic noises - as well as to interact with other specific board functions.A simulation environment was achieved for the digital demodulator in Matlab, allowing the results verification and allowing to establish others testing scenariosMestradoTelecomunicações e TelemáticaMestre em Engenharia Elétric