Concepts for Short Range Millimeter-wave Miniaturized Radar Systems with Built-in Self-Test

This work explores short-range millimeter wave radar systems, with emphasis on miniaturization and overall system cost reduction. The designing and implementation processes, starting from the system level design considerations and characterization of the individual components to final implementation of the proposed architecture are described briefly. Several D-band radar systems are developed and their functionality and performances are demonstrated

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

Non-Contact Human Motion Sensing Using Radar Techniques

Human motion analysis has recently gained a lot of interest in the research community due to its widespread applications. A full understanding of normal motion from human limb joint trajectory tracking could be essential to develop and establish a scientific basis for correcting any abnormalities. Technology to analyze human motion has significantly advanced in the last few years. However, there is a need to develop a non-invasive, cost effective gait analysis system that can be functional indoors or outdoors 24/7 without hindering the normal daily activities for the subjects being monitored or invading their privacy. Out of the various methods for human gait analysis, radar technique is a non-invasive method, and can be carried out remotely. For one subject monitoring, single tone radars can be utilized for motion capturing of a single target, while ultra-wideband radars can be used for multi-subject tracking. But there are still some challenges that need to be overcome for utilizing radars for motion analysis, such as sophisticated signal processing requirements, sensitivity to noise, and hardware imperfections. The goal of this research is to overcome these challenges and realize a non-contact gait analysis system capable of extracting different organ trajectories (like the torso, hands and legs) from a complex human motion such as walking. The implemented system can be hugely beneficial for applications such as treating patients with joint problems, athlete performance analysis, motion classification, and so on

Noncontact Vital Signs Detection

Human health condition can be accessed by measurement of vital signs, i.e., respiratory rate (RR), heart rate (HR), blood oxygen level, temperature and blood pressure. Due to drawbacks of contact sensors in measurement, non-contact sensors such as imaging photoplethysmogram (IPPG) and Doppler radar system have been proposed for cardiorespiratory rates detection by researchers.The UWB pulse Doppler radars provide high resolution range-time-frequency information. It is bestowed with advantages of low transmitted power, through-wall capabilities, and high resolution in localization. However, the poor signal to noise ratio (SNR) makes it challenging for UWB radar systems to accurately detect the heartbeat of a subject. To solve the problem, phased-methods have been proposed to extract the phase variations in the reflected pulses modulated by human tiny thorax motions. Advance signal processing method, i.e., state space method, can not only be used to enhance SNR of human vital signs detection, but also enable the micro-Doppler trajectories extraction of walking subject from UWB radar data.Stepped Frequency Continuous Wave (SFCW) radar is an alternative technique useful to remotely monitor human subject activities. Compared with UWB pulse radar, it relieves the stress on requirement of high sampling rate analog-to-digital converter (ADC) and possesses higher signal-to-noise-ratio (SNR) in vital signs detection. However, conventional SFCW radar suffers from long data acquisition time to step over many frequencies. To solve this problem, multi-channel SFCW radar has been proposed to step through different frequency bandwidths simultaneously. Compressed sensing (CS) can further reduce the data acquisition time by randomly stepping through 20% of the original frequency steps.In this work, SFCW system is implemented with low cost, off-the-shelf surface mount components to make the radar sensors portable. Experimental results collected from both pulse and SFCW radar systems have been validated with commercial contact sensors and satisfactory results are shown

Multifunction Transceiver Architecture and Technology for Future Wireless Systems

RÉSUMÉ Depuis la toute première transmission sans fil, les ondes radiofréquences ont été progressivement mises en valeur et exploitées dans un nombre de plus en plus important d'applications. Parmi toutes ces applications, la détection et la télécommunication sont sans doute les plus indispensables de nos jours. Il existe un grand nombre d’utilisations des radiofréquences, incluant les transports intelligents pour lesquels les véhicules doivent être équipés à la fois de radars et de dispositifs de communication afin d’être capables de détecter l'environnement ainsi que de réaliser la communication avec d'autres unités embarquées. La technologie émergente 5G est un autre exemple pour lequel plusieurs capteurs et radios devraient être capables de coopérer de manière autonome ou semi-autonome. Les principes de fonctionnement des systèmes radars et radio sont toutefois différents. Ces différences fondamentales peuvent entraîner l'utilisation de différentes architectures de traitement du signal et d'émetteur-récepteur, ce qui peut poser des problèmes pour l'intégration de toutes les fonctions requises au sein d'une seule et même plate-forme. En dehors de cela, certaines applications requièrent plusieurs fonctions simultanément dans un même dispositif. Par exemple, les systèmes de détection d'angle d'arrivée 2D nécessitent d'estimer l'angle d'arrivée (AOA) du faisceau entrant dans les plans horizontal et vertical simultanément. La communication radio multi-bandes et multi-modes est un autre exemple pour lequel un système radio doit être capable de communiquer dans plusieurs bandes de fréquences et dans plusieurs modes, par exemple, un duplexage en fonction de la fréquence ou du temps. À première vue, on peut penser que l'assemblage de plusieurs dispositifs distincts n'est pas la meilleure solution en ce qui concerne le coût, la simplicité et la fonctionnalité. Par conséquent, une direction de recherche consiste à proposer une architecture d'émetteur-récepteur unifiée et compacte plutôt qu’une plate-forme assemblant de multiples dispositifs distincts. C’est cette problématique qui est spécifiquement abordée dans ce travail. Selon les fonctions à intégrer dans un seul et unique système multifonctionnel, la solution peut traiter plusieurs aspects simultanément. Par exemple, toute solution réalisant l'intégration de fonctions liées au radar et à la radio devrait traiter deux aspects principaux, à savoir : la forme d'onde opérationnelle et l'architecture frontale RF.----------ABSTRACT Since the very early wireless transmission of radiofrequency signals, it has been gradually flourished and exploited in a wider and wider range of applications. Among all those applications of radio technology, sensing and communicating are undoubtedly the most indispensable ones. There are a large number of practical scenarios such as intelligent transportations in which vehicles must be equipped with both radar and communication devices to be capable of both sensing the environment and communication with other onboard units. The emerging 5G technology can be another important example in which multiple sensors and radios should be capable of cooperating with each other in an autonomous or semi-autonomous manner. The operation principles of these radar and radio devices are different. Such fundamental differences can result in using different operational signal, distinct signal processing, and transceiver architectures in these systems that can raise challenges for integration of all required functions within a single platform. Other than that, there exist some applications where several functions of a single device (i.e. sensor or radio) are required to be executed simultaneously. For example, 2D angle-of-arrival detection systems require estimating the angle of arrival (AOA) of the incoming beam in both horizontal and vertical planes at the same time. Multiband and multimode radio communication is another example of this kind where a radio system is desired to be capable of communication within several frequency bands and in several modes, e.g., time or frequency division duplexing. At a first glance, one can feel that the mechanical assembling of several distinct devices is not the best solution regarding the cost, simplicity and functionality or operability. Hence, the research attempt in developing a rather unified and compact transceiver architecture as opposed to a classical platform with assembled multiple individual devices comes out of horizon, which is addressed specifically in this work. Depending on the wireless functions that are to be integrated within a single multifunction system, the solution should address multiple aspects simultaneously. For instance, any solution for integrating radar and radio related functions should be able to deal with two principal aspects, namely operational waveform and RF front-end architecture. However, in some other above- mentioned examples such as 2D DOA detection system, identical operational waveform may be used and the main challenge of functional integration would pertain to a unification of multiple mono-functional transceivers

Experimental low-THz imaging radar for automotive applications

This thesis reports initial experimental results that provide the foundation for low-THz radar imagery for outdoor scenarios as expected in automotive sensing. The requirements for a low-THz single imaging radar sensor are outlined. The imaging capability of frequency-modulated continuous-wave (FMCW) radar operating at 150 GHz is discussed. A comparison of experimental images of on-road and off- road scenarios made by a 150 GHz FMCW radar and a reference 30 GHz stepped frequency radar is made, and their performance is analysed

Integrated Communication and Radar Scheme for Future Intelligent Transportation Systems

RÉSUMÉ Grâce à son impact social et économique, la journée mondiale de la santé 2004 a été dédiée à la sécurité routière. Le thème suivant : « La sécurité routière n‘est pas accidentelle» a été abordé. Suite à cette rencontre, une attention toute particulière a été donnée à la problématique des accidents de la route. Afin d‘augmenter la sécurité sur les routes et diminuer le nombre d‘accidents, des systèmes intelligents de transport (ITS) ont été proposés. Ces systèmes utilisent les technologies avancées de communication et de détection. La structure ITS associe les fonctionnalités des Radars et des communications sans fils, permettant de rendre les futurs véhicules intelligents autonomes et collaboratifs. Ces deux fonctions peuvent être réalisées en utilisant deux systèmes radiofréquences individuels et indépendants. Toutefois, une meilleure solution consiste à intégrer, dans un seul dispositif, le système de communication et le radar. Ceci permet d‘apporter de nombreux avantages comme par exemple la simplification et la miniaturisation du système, sa reconfigurabilité, l‘augmentation de son efficacité, et enfin cela permettrait de réduire fortement ses coûts de développement et de réalisation, élément clé pour réussir la commercialisation du véhicule intelligent. Intrinsèquement, le fonctionnement des communications sans fils et des Radar ne sont pas compatibles. En effet, ils requièrent des techniques de conception et d‘implémentations différentes, ce qui les rend difficilement intégrables en un seul système. Afin de répondre aux grands défis technologiques présentés par cette intégration fonctionnelle, cette thèse de doctorat présente un développement compréhensif des systèmes intégrés de communication sans-fil et radar (iCars), placés dans un seul dispositif émetteur-récepteur et destinés aux futurs systèmes intelligents de transport. Premièrement, après une recherche bibliographique approfondie, une nouvelle technique de modulation est proposée. Dans cette technique, les signaux radar et les signaux de communication sont arrangés en créneaux temporels séquentiels pendant un cycle d‘opération, minimisant ainsi leurs interférences mutuelles. Cette technique permet d‘obtenir une agilité temporelle et/ou une reconfigurabilité fonctionnelle, par l‘ajustement adaptatif ou cognitif de toutes les durées de modulation de la forme d‘onde, en accord avec les situations spécifiques de l‘utilisation.----------ABSTRACT Due to its growing social and economic impact, the world health day of 2004 was dedicated to road safety with its theme as ―Road safety is no accident‖. Thereafter, road traffic accidents have received unprecedented attention. In order to improve road safety, intelligent transportation systems (ITSs) have been proposed and deployed by making use of advanced information and communication technologies. Within the framework of ITSs, both wireless communication and radar sensing functions are indispensable for autonomous and cooperative operations of future intelligent vehicles (IVs). These two functions can definitely be achieved by using two individual and independent wireless systems. However, an attractive solution would be to integrate both communication and radar functions within a single transceiver platform, which could bring a lot of benefits such as system simplification and miniaturization, functional reconfiguration and fusion (mutual penetration and rapid processing/control of information), and especially efficiency enhancement and cost reduction that are the keys to the successful development and marketing of IVs. Intrinsically, wireless communication and radar systems have incompatible operation principles, which require different design considerations and system implementations with respect to modulation techniques, required bandwidth, signal propagation and detection. To respond to these unprecedented design and technological challenges posed by the functional integration, this PhD thesis presents comprehensive study and development of integrated communication and radar systems (iCars) based on a single transceiver platform for future ITSs. Following a broad and in-depth literature review, first of all, a novel modulation scheme is proposed in this work, in which radar and communication signals are arranged in sequential time slots of one operation cycle and therefore, their interference is minimized. Also, time-agility or flexible functional reconfiguration can be easily achieved by adaptively or cognitively adjusting all software-programmable time durations in the modulation waveform according to usage situations. Moreover, functional fusion between two operation modes can be made possible from the following two aspects. One is that targets‘ ranges and velocities obtained through the radar mode can be used in the communication mode to mitigate multipath fading and compensate the Doppler spreading effect caused by the mobility of onboard units

High Performance Integrated Beam-Steering Techniques for Millimeter-Wave Systems

Recently, the research and development of low cost and highly efficient millimeter-wave (mmWave) systems with beam-steering capabilities have significantly advanced to address the ever-increasing demand for future wireless ultra-broadband applications. These applications include, but are not limited to, automotive anti-collision surveillance radar, smart navigation systems, improved wireless tracking, satellite communication, imaging, 5G wireless communication, and 60GHz multi-gigabit wireless personal and local area network (WPAN/WLAN). In general, beam-steering capability significantly relaxes the overall system power budget and minimizes the interference. In communication applications, it enhances the link robustness through multi-path mitigation and increases the channel and the aggregated channel throughput by exploiting the spatial dimension. In imaging/radar systems, beam-steering is essential for achieving the required resolution (angle-of-arrival). In this work, I have proven many beam-steering advantages in this work through the development of a ray-tracing based wireless channel model, which has been used to extract the antenna system requirements and to quantitatively illustrate the usefulness of the presented beam-steerable systems. Despite the advantages it provides, the realization of this electronic beam-steerable mmWave antenna system is quite challenging. In general, the mmWave components' design, integration, fabrication and testing processes are far more complex than their lower frequency counterparts. This can be attributed to the significant losses and parasitics experienced at mmWave frequencies, as well as the lack of reliable design models. Systems with fully integrated (on-chip) antennas and passives have been widely studied and presented at mmWave range; however, the performance (low antenna gain, high phase noise, etc…), the cost (die size is huge), and thermal problems are still major issues for these systems. Hybrid integration tackles these problems by combining a compact and low power consumption die (or multiple dies) with high performance off-chip passives (antenna, feed network, passive phase shifters, resonators, etc…); however, this integration is costly. In addition, there is a challenge associated with the implementation of high performance components at mmWave range. This is mainly due to the use of advanced/non-standard types of fabrication technologies and complex integration/packaging techniques. Investigation, optimization, development of a highly efficient and yet very low cost mmWave beam-steering solution calls for a multi-disciplinary approach which involves EM theory, optimization techniques, microwave circuits, wireless communications, Silicon micro-fabrication, layout design, parasitics modeling/extraction and MEMS technology. The proposed study introduces a high performance beam-steering mmWave antenna system along with its integration with the active components with special consideration to the fabrication cost. The new high resistivity Silicon (HRS) dielectric waveguide (DWG) based platform, which has recently been developed at CIARS (Centre for Intelligent Antenna and Radio Systems), is extended and used for wireless mmWave systems with beam-steering antennas. Electronic beam-steering can be implemented through beam-switching configurations (simple, fast but coarse) or phase array configurations (complex but high performance for large arrays). A novel low cost, highly efficient and compact switched-beam antenna is proposed for the automotive radar application. The design optimization along with the fabrication and measurement details have been discussed. For phased array applications, various HRS DWG-based antenna designs have been proposed and discussed in this study. Among them is the novel pixelated antenna which represents a new systematic procedure for designing a compact and low cost dielectric antenna for mmWave/sub-THz applications. I have developed a method using Genetic Algorithm to optimize the shape of the antenna in a compact space for any given specifications. The other important component is the phase shifter. Low-cost, compact and easily integrated phase shifters with low insertion loss and low power consumption are highly desirable for a wide range of applications. In addition, minimal insertion loss variations for the full range of phase shift over a wide frequency band is a critical requirement. I have carefully studied the effects of phase shifters non-idealities, taking into consideration the phased array system level requirements and presented two novel HRS DWG-based phase shifters. Among the proposed phase shifters is a structure that changes the phase of the propagating mode by varying the propagation constant using a high dielectric constant (40-170) slab of Barium Lanthanide Tetratitanates. This leads to a compact phase shifter design. The additional advantage of this phase shifter is that it focuses the fields in a lossless air gap (new low loss guiding structure). Different types of the proposed phase shifter have been developed and successfully tested including electrically controlled ones. Finally, I present new techniques for low cost and efficient integration for the proposed high quality mmWave passives with active components.4 month

UWB Pulse Radar for Human Imaging and Doppler Detection Applications

We were motivated to develop new technologies capable of identifying human life through walls. Our goal is to pinpoint multiple people at a time, which could pay dividends during military operations, disaster rescue efforts, or assisted-living. Such system requires the combination of two features in one platform: seeing-through wall localization and vital signs Doppler detection. Ultra-wideband (UWB) radar technology has been used due to its distinct advantages, such as ultra-low power, fine imaging resolution, good penetrating through wall characteristics, and high performance in noisy environment. Not only being widely used in imaging systems and ground penetrating detection, UWB radar also targets Doppler sensing, precise positioning and tracking, communications and measurement, and etc. A robust UWB pulse radar prototype has been developed and is presented here. The UWB pulse radar prototype integrates seeing-through imaging and Doppler detection features in one platform. Many challenges existing in implementing such a radar have been addressed extensively in this dissertation. Two Vivaldi antenna arrays have been designed and fabricated to cover 1.5-4.5 GHz and 1.5-10 GHz, respectively. A carrier-based pulse radar transceiver has been implemented to achieve a high dynamic range of 65dB. A 100 GSPS data acquisition module is prototyped using the off-the-shelf field-programmable gate array (FPGA) and analog-to-digital converter (ADC) based on a low cost solution: equivalent time sampling scheme. Ptolemy and transient simulation tools are used to accurately emulate the linear and nonlinear components in the comprehensive simulation platform, incorporated with electromagnetic theory to account for through wall effect and radar scattering. Imaging and Doppler detection examples have been given to demonstrate that such a “Biometrics-at-a-glance” would have a great impact on the security, rescuing, and biomedical applications in the future