学术报告

Title:         Metamaterial-Based Micro-Electromechanical Ultra-Compact Non-Dispersive Phase Shifters

Time:        15：00，28 Nov., 2011

Location:   Meeting Room 3－208 of Information Buildings (电信楼群3号楼208会议室)

Sperker:     James C. M. Hwang, Professor at Lehigh University, USA, IEEE FELLOW

Sponsors:   IEEE MTT-S Shanghai Chapter

                  Key Laboratory of Ministry of Education of China for Research of Design and Electromagnetic Compatibility of High Speed Electronic Systems, Shanghai Jiao Tong University（上海交通大学高速电子系统设计与电磁兼容教育部重点实验室）

Abstract

Recent advances in metamaterials allow non-dispersive phase shifters to be realized, which will greatly simplify the operation of frequency-agile and broadband-modulated phased-array radar and communications systems. Dispersion is only natural, so the phase of a conventional true-time-delay phase shifter varies with frequency. However, by judiciously combining right-handed natural material and left-handed metamaterial with different dispersion characteristics, a phase shifter can have constant phase shift across a wide bandwidth. For example, a composite right/left-handed (CRLH) transmission line can be formed by combining fixed inductors with variable capacitors. The CRLH transmission line can then assume right- or left-handed characteristics depending on the values of the variable capacitors. The variable capacitors can be based on micro-electromechanical (MEM) capacitive switches, which can be monolithically integrated in a CRLH transmission line to realize non-dispersive phased shifters that are light, compact, low loss, low cost, and low power consumption. The additional degrees of freedom afforded by the MEM switches also allow a slow-wave structure to be tightly wrapped around the MEM switches to further reduce the size and loss of the phase shifter while maintaining wideband impedance match. Experimental results obtained on a Ku-band phase-shifter unit cell will be used to illustrate these design principles and performance advantages.

Biography

James C. M. Hwang is a Professor of Electrical Engineering and Director of the Compound- Semiconductor Technology Laboratory at Lehigh University. He graduated with a B.S. degree in Physics from National Taiwan University in 1970, and completed M.S. (1973) and Ph.D. (1976) studies in Materials Science at Cornell University. After twelve years of industrial experience at IBM, AT&T, GE, and GAIN, he joined Lehigh University in 1988. His current research interests include micro-electromechanical systems, radio-frequency transistors and integrated circuits, optoelectronics and bio-electromagnetics. He has been an Advisory Professor at Shanghai Jiao Tong University.. He has published approximately 300 refereed technical papers and has been granted five U. S. patents. He became an IEEE Fellow in 1994. He received the IBM Faculty Award in 2007, the CIE Outstanding Achievement Award, and the WOCC Outstanding Contribution Award in 2011.