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Zhi Ning Chen

Zhi-Chen

Zhi Ning Chen
Institute for Infocomm Research
20 Science Park Road
#02-21/25 Teletech Park, Singapore 117674
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Dr Zhi Ning Chen received his BEng, MEng, and PhDs degrees all in Electrical Engineering from the Institute of Communications Engineering (ICE), China and University of Tsukuba, Japan, respectively. During 1988-1995, he worked at ICE as Lecturer and later Associate Professor, as well as at Southeast University, China as a Postdoctoral Fellow and later as an Associate Professor. During 1995-1997, he joined the City University of Hong Kong as a Research Assistant and later a Research Fellow. In 1997, he was awarded a JSPS Fellowship to conduct his research at the University of Tsukuba, Japan. In 2001 and 2004, he visited the University of Tsukuba under a JSPS Fellowship Program (senior level). In 2004, he worked at IBM T. J. Watson Research Center, USA as an Academic Visitor.

Since 1999, he has worked with the Institute for Infocomm Research (formerly known as Center for Wireless Communications and the Institute for Communication Research) as Member of the Technical Staff (MTS), Principal MTS, Senior Scientist, and Lead Scientist. He is currently appointed as Principal Scientist and Department Head for RF & Optical and concurrently holds Visiting/Adjunct/Guest Professor appointments at Southeast University, Nanjing University, Shanghai Jiao Tong University, Tsinghua University, Tongji University, Dalian Maritime University, and the National University of Singapore. He was appointed as an Adjunct Professor/Associate Professor at Zhejiang University and Nanyang Technologies University.

Dr Chen has organized many international events as the general chair, technical program committee chair, and as a key member of organizing committees. He is the founder of the International Workshop on Antenna Technology (iWAT). He has published 290 journal and conference papers as well as authored and edited books entitled Broadband Planar Antennas, UWB Wireless Communication, Antennas for Portable Devices, and Antennas for Base Station in Wireless Communications. He also contributed to the books UWB Antennas and Propagation for Communications, Radar, and Imaging as well as Antenna Engineering Handbook. He is holding 25 granted and filed patents with 21 licensed deals with industry. He is the recipient of the CST University Publication Award 2008, IEEE AP-S Honorable Mention Student Paper Contest 2008, IES Prestigious Engineering Achievement Award 2006, I2R Quarterly Best Paper Award 2004, and IEEE iWAT 2005 Best Poster Award. His current research interest includes applied electromagnetics, antennas for applications of microwaves, mmW, submmW, and THz in communication and imaging systems. Dr Chen is a Fellow of the IEEE for his contribution to small and broadband antennas for wireless applications. (www1.i2r.a-star.edu.sg/~chenzn)

Miniaturization of Ultra-wideband Antennas

About the Talk: Ultra-wideband (UWB) has become the promising wireless technology in commercial applications such as next-generation short-range high-data-rate wireless communications, high resolution imaging, and high accuracy radar. The antenna is one of the key designs in UWB wireless systems. This talk starts with a brief introduction to design challenges of UWB antennas, followed by state-of-the-art solutions. Next, miniaturization technologies for UWB antennas are addressed. Planar designs are highlighted due to their unique merits and wide adoption in practical applications. First, a newly developed technique to achieve ground-independent UWB antenna performance, one of the most challenging issues in small antenna design, is addressed. A design example is used to elaborate the mechanism of the method. Based on this concept, an antenna with further reduced size is designed to fit wireless USB dongles. Furthermore, an innovative compact diversity UWB antenna shows the advantage of ground-independence for small antennas in diversity applications. Last, UWB antennas co-designed with filtering performance using bandpass/bandstop filters integrated into the antenna are proposed to reduce the overall size of devices and enhance antenna performance. At the end, the trends of UWB antenna R&D are discussed, correlated with applications and market demands.

Design Considerations of Antennas in MIMO Systems -from Antenna Engineering Perspectives

About the Talk: This talk will present and discuss the key design considerations for antennas in multiple-input-multiple-output (MIMO) wireless communication systems from antenna engineering perspectives. First, the effects of antenna design on diversity performance of MIMO systems will be analyzed. This will show that the configurations of the antennas can greatly affect system performance; in particular, the signal correlation at both the transmitters and the receivers in both the uplink and the downlink. Second, the effects on the envelope correlation and capacity of MIMO systems will be evaluated by using antenna parameters, namely S-parameters and radiated electric fields. In particular, the antenna efficiency that is affected by inter-element mutual coupling is taken into account in the antenna design. Third, the concepts of two-dimensional and three-dimensional envelope correlation coefficient distributions are introduced and discussed. As a result, the performance of MIMO systems, especially for pattern diversity, can be further optimized instead of using the conventional average envelope correlation coefficients. Fourth, the concept of overall correlation of the system is proposed to evaluate the diversity performance of MIMO systems, which will, for example, include spatial, polarization, and pattern diversity. After that, the design considerations for antennas in MIMO systems are presented from an antenna engineering point of view. Last, a compact three-element MIMO antenna system designed for indoor 2.4 GHz WLAN applications is exemplified to validate the design considerations proposed here. Moreover, the technology to reduce inter-element mutual coupling is also introduced and applied to the three-element design.

(Proposed): Antennas for RFID Tags and Readers

About the Talk: Radio frequency identification (RFID) technology has been rapidly developing in recent years and the applications have been widely found in service industries, distribution logistics, manufacturing companies, and product-flow systems. Antenna design for readers and tags is one of the key factors for RFID systems. The optimized tag and reader antenna design will benefit RFID systems with longer reading range, better detection accuracy, lower fabrication cost, and simple system configuration and implementation. This talk will start with a brief introduction to RFID systems, which may be active, passive, or semi-active systems, and operate at LF, HF, UHF, or MW bands. Then the key considerations related to the antenna design for tags and readers will be addressed from system perspectives. After that, case studies will highlight specific challenges for antennas in the HF near-field and UHF near/far-field systems. In particular, important engineering factors such as environmental effects vs. co-design methodology, size constraints, cost constraints, and UHF near-field reader antenna coverage will be presented with corresponding practical design cases.