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Joshua Le-Wei Li

Li Wei Li

Prof. Joshua Le-Wei Li (Deceased)
School of Electronic Engineering, Director, Institute of Electromagnetics
University of Electronic Science and Technology of China
2006 Xi-Yuan Avenue, Western High-Tech District, Chengdu, China 611731
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Joshua Le-Wei Li (SM'96-F'05) received his Ph.D. degree in Electrical Engineering from Monash University, Melbourne, Australia, in 1992. He was, as a Research Fellow, with Department of Electrical & Computer Systems Engineering at Monash University, sponsored in 1992 by Department of Physics at La Trobe University, both in Melbourne, Australia. Between 1992-2010, he was with the Department of Electrical & Computer Engineering at the National University of Singapore where he was a tenured Full Professor and the Director of NUS Centre for Microwave and Radio Frequency. In 1999-2004, he was seconded with High Performance Computations on Engineered Systems (HPCES) Programme of Singapore-MIT Alliance (SMA) as a SMA Faculty Fellow.

 

In May-July 2002, he was a Visiting Scientist in the Research Laboratory of Electronics at Massachusetts Institute of Technology (MIT), Cambridge, USA; in October 2007, an Invited Professor with University of Paris VI, France; and in January and June 2008, an Invited Visiting Professor with Institute for Transmission, Waves and Photonics at Swiss Federal Institute of Technology, Lausanne (EPFL) in Switzerland. Currently, he is with School of Electronic Engineering at University of Electronic Science and Technology of China, Chengdu, China where he is a QRJH Chair (or National) Professor and a founding Director of Institute of Electromagnetics. His current research interests include electromagnetic theory (e.g., dyadic Green's functions), computational electromagnetics (e.g., pre-corrected fast Fourier transform - P-FFT method and adaptive integral method -AIM), radio wave propagation and scattering in various media (e.g., chiral media, anisotropic media, bi-anisotropic media and metamaterials), microwave propagation and scattering in tropical environment, and analysis and design of various antennas (e.g., loop and wire antennas and microstrip antennas). In these areas, he has (co-)authored 2 books (namely, Spheroidal Wave Functions in Electromagnetic Theory (New York: Wiley, 2001); Device Modeling in CMOS Integrated Circuits: Interconnects, Inductors and Transformers (London: Lambert Academic Publishing, 2010), 48 book chapters, over 310 international refereed journal papers (of which more than half were published in IEEE Transactions and Letters, and the remaining in Optics Express, Physical Review E or B, Radio Science, IEE Proceedings, and JEWA etc), 48 regional refereed journal papers, and over 350 international conference papers. He has graduated about 70 Master-degree and PhD-degree students, and mentored over 20 post-doctoral fellows and research scientists.

Prof. Li was a recipient of a few awards including 2 best paper awards from the Chinese Institute of Communications and the Chinese Institute of Electronics, the 1996 National Award of Science and Technology of China, the 2003 IEEE AP-S Best Chapter Award when he was the IEEE Singapore MTT/AP Joint Chapter Chairman, and the 2004 University Excellent Teacher Award of National University of Singapore. He has been a Fellow of IEEE since 2005 and a Fellow of The Electromagnetics Academy since 2007 (selected member since 1998) and was IEICE Singapore Section Chairman between 2002-2007. As a regular reviewer of many archival journals, he is currently an Associate Editor of Radio Science and International Journal of Antennas and Propagation; an Editorial Board Member of Journal of Electromagnetic Waves and Applications (JEWA), the book series Progress In Electromagnetics Research (PIER) by EMW Publishing, International Journal of Microwave and Optical Technology, and Electromagnetics journal; and an Overseas Editorial Board Member of Chinese Journal of Radio Science and Frontiers of Electrical and Electronic Engineering in China (for selected papers from Chinese Universities by Springer). He was also a Guest Editor of a Special Section on ISAP 2006 of IEICE Transactions on Communications, Japan. He also serves as a member of various International Advisory Committee and/or Technical Program Committee of many international conferences or workshops, in addition to serving as a General Chairman of ISAP2006 & IWM2009 and TPC Chairman of PIERS2003, iWAT2006 and APMC2009.

Wideband and Low-Loss Metamaterials for Microwave and RF: Fast Algorithm and Applications

Over the past several years, the metamaterials research has been intensively conducted for the microwave and radio frequency (RF) applications. However, difficulties were faced and are still being faced right now in the developments of (1) efficient solvers and/or tools for metamaterial designs; and (2) design and fabrications of metamaterials of low loss and broad frequency bandwidth. Although these are not key issues in optical region, they are in fact the major issues of the metamaterial research in microwave and RF region. This talk is split into two major parts: (1) the first is to look into the EM wave properties in metamaterials and to develop efficient solvers for their designs; and (2) the second is to try to design the metamaterials for antenna applications.

For the efficient algorithms developed, the integral equation solvers accelerated using the adaptive integral (equation) method (AIM) and also the pre-corrected fast Fourier transform (pFFT) technique were developed and various examples in the designs will be demonstrated. In the second case, a single antenna designed using the metamaterial properties is considered, designed, fabricated, and measured. It is shown that the new design of the metamaterial antenna has a low loss (or high gain) and a broad bandwidth and this was never achieved using the conventional technique. The development of the metamaterial antennas was further extended to an array antenna and some interesting and promising results will be provided. A comprehensive review on the to-date progress on the metamaterials will be also provided.

Fast Solvers Based on Hybrid FFT-Integral Equations for Design & Analysis of Large Scaled Systems

In computational electromagnetics, three common methods are mostly frequently applied in the community for solving various practical applications, namely, (a) finite-difference time-domain (FDTD) method, (b) finite element method (FEM), and (c) integral equation method (IEM) including the method of moments (MoM) and the boundary element method (BEM). For very large scaled problems, the fast solvers are needed to accelerate the solution process. Associated with the large scaled problems, the FEM and IEM are very efficient to handle. To accelerate the IEM or MoM solution procedure, the fast multipole method (or its high level version, multi-level fast multipole algorithm (MLFMA)) and the fast-Fourier-transform based methods are very popular to use. In this talk, 3 fast algorithms developed based on integral equations and fast Fourier transform will be presented, namely, Conjugate Gradient Fast Fourier Transform (CG-FFT) Technique, Adaptive Integral (Equation) Method (AIM), and Precorrected Fast Fourier Transform (pFFT) method. These 3 methods have found extensive applications in the printed circuit designs, antenna analysis and design, radar cross section control, etc. Together with the latest growth of the computer facilities and advances of computing power, these techniques developed have made many past unsolved large scaled electrical engineering problems to be solvable. Some practical examples were solved using these techniques and results obtained using them will be demonstrated so as to show the accuracy, efficiency, and applicability of these techniques developed only the recent decade. Comparative studies using above different techniques are also presented to show the efficiency and accuracy, with emphasis given to the respective advantages and disadvantages of the above different groups of methods.