学术讲座通知 演讲人:Prof. Mingyu Lu (Assistant Professor, Department of EE, The University of Texas at Arlington) 题目: Ultra-Wideband (UWB) Antennas and Circuits in Communication and Radar 时间: 12月22日下午14: 00-15: 30 地点: 东南大学李文正楼612北会议室 主办: 东南大学毫米波国家重点实验室 IEEE AP-MTT-EMC Joint Nanjing Chapter 江苏省电子学会天线与微波专业委员会 ----------------------------------------------------------------------------------------- Abstract: In this presentation, some research work on ultra-wideband (UWB) in the Wave Scattering Research Center (WSRC), the University of Texas at Arlington (UTA), is reviewed. UWB technology has attracted enormous attention, since the Federal Communications Commission (FCC) authorized unlicensed use of UWB in 3.1 - 10.6 GHz in February 14, 2002. Compared with traditional narrow-band wireless technologies, UWB offers higher data rate, more immunity to multi-path fading, lower power consumption, less cost, and less complexity. Therefore, it is believed to one of the potential candiates for next-generation communication and radar systems. This talk describes three UWB-related research efforts currently ongoing at WSRC of UTA. (1) An UWB radar sensor network. This projects aims at developing low-cost and low-power radar sensors that could be mass manufactured and deployed over a large area for long-term monitoring purposes. A wideband omni-directional antenna and an UWB transceiver are designed and integrated. Specifically, a quasi-planar conical antenna will be discussed in detail. Simulation and measurement results show that, the quasi-planar conical antenna is wideband (matched to 50-ohm from 1 GHz to 20 GHz) and omni-directional. At the same time, it is mechanically robust, light, of low-cost, and easy to fabricate and re-configure. In the anechoic chamber of WSRC, a radar sensor network testbed is constructed and tested for passive target detection. Both metallic and dielectric targets with various physical sizes are experimented. Multiple algorithms are applied for the target localization, including Iteratively Refined - Minimum Mean Square Estimate, Hough Transform, and Grid Based Location Estimation. A modified grid based algorithm is demonstrated to offer the best performance in presence of large range estimation errors. (2) An UWB car-borne radar system. In this research, 22 - 29 GHz UWB band is exploited to realize a compact and low-cost UWB radar for safety systems on commercial vehicles (i.e., for anti-collision, blind spot detection, and parking aid purposes). System simulations demonstrate that, the propopsed UWB car-borne radar covers 360-degree range around the vehicle and has detection distance up to 30 meters. It is composed of four radar sensors, located at the front, back, and two sides of the car, respectively. Each of them is composed of an antenna array, duplexers, a transmitter, a receiver, and a digital signal processing unit. A novel cavity-backed slot antenna is designed for this car-borne radar system. It is planar and conformal, hence can be readily installed onto the car body. A full wave numerical solver is developed and two antenna protypes are fabricated and measured. Simulation and measurement results have nice agreements, and they show more than 30% relative bandwidth. (3) A circuit implementation of time reversal for UWB systems. Time reversal is a popular research topic in recent years, largely due to the development of UWB. Since time reversal achieves "focusing" in both space and time, combination of UWB and time reversal opens gates to many novel applications in communication and radar. Time reversal has been applied to acoustics, electromagnetics, and optics. However, compared to acoustics and optics, time reversal in electromagnetics is not so developed. A critical difficulty lies on how to time reverse impulses with short temporal durations (e.g., at nano-second level) in practice. We designed a pracitcal circuit to resolve this difficulty. Specifically, the proposed circuit obtains the impulse's discrete spectrum first; then accomplishes time-reversal in the frequency domain; and finally synthesizes the output using discrete continuous wave elements. This circuit consists of practical and commercially available components; hence is low-cost and easy to implement. Its performance is demonstrated by Advanced Design System (ADS) simulation. Furthermore, together with Maxwell's equations solvers, it is verified that this circuit could achieve temporal and spatial focusing in realistic environments. Biography ofMingyu Lu: Mingyu Lu received the B.S. and M.S. degrees in electrical engineering from Tsinghua University, Beijing, China, in 1995 and 1997 respectively, and the Ph.D. degree in electrical engineering from the University of Illinois at Urbana-Champaign in 2002. From 1997 to 2002, he was a research assistant at the Department of Electrical and Computer Engineering in the University of Illinois at Urbana-Champaign. From 2002 to 2005, he was a postdoctoral research associate at the Electromagnetics Laboratory in the University of Illinois at Urbana-Champaign. He joined the faculty of the Department of Electrical Engineering, the University of Texas at Arlington as an assistant professor in 2005. His current research interests include radar systems, microwave remote sensing, antenna design, and computational electromagnetics. He was the recipient of the first prize award in the student paper competition of 2001 IEEE AP-S International Symposium and USNC/URSI National Radio Science Meeting, Boston, MA, 2001. He currently serves as the chair of Antennas and Propagation Society of IEEE Fort Worth Chapter. | ||
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