Spatial Characterization of MIMO Radiation Terminals: A Novel Approach

Nima Jamaly
Chalmers University of Technology, Sweden

Tuesday, August 24, 2010 at 11:00am
Engr IV Faraday Room 67-124

Abstract

Electromagnetic characterization of Multiple-Input and Multiple Output (MIMO) terminals has been of contemporary concern for the last decade. Performance of MIMO terminals is dependent not only on design and spatial configuration of the elements themselves, but also on properties of the multipath environments in which they operate. The latter exerts its influence on characterizing the terminals making it difficult to introduce a criterion for their judgment. This restriction prompted investigations in search of enhanced models representing real multipath environments. Different models have been purposed for azimuth planes among which a uniform distribution of angle of arrival is the most common one. Moreover, several models were also suggested for elevation plane, e.g. Gaussian, Laplacian, double exponential and uniform.

In this presentation, a novel model of simulating the performance of multi-element terminals in multipath environments is introduced providing a unique and intriguing opportunity to assess their advantages in any kind of fading environment, e.g. Rayleigh, Double-Rayleigh, Rician etc and for any type of distribution of angle of arrival. The approach resides on spatial domain characterization and bestows a considerable insight into general performance of multi-element terminals.

Furthermore, different well-known gauges like correlation, TARC and radiation efficiencies are detailed to a point of satisfaction. The concepts of MEG and MED and the notion of Decoupling Efficiency are explained and new analytical closed-form formulas are given for their evaluation. A few minutes are dedicated to a novel way of assessing the bandwidth of multi-element terminals by means of Mean Decoupling Efficiencies.

Finally, advantage of beam-forming technique is investigated in details where capacity and diversity gain results are illustrated. We will -for the first time- demonstrate how richness of a multipath environment affects the performance of these terminals. To enrich our talk, several practical examples and verifying measurement results are also presented.

Biography
Nima Jamaly was born in Iran in 1979. He received the BSc degree in Electrical Engineering (EE) - Telecommunications in 2002, an MSc degree in EE - Telecommunications with specialization in Computational Electromagnetics in 2006 and an MSc degree in EE - Microwave and Photonics in 2008. He is currently pursuing a PhD degree in Electromagnetics at Chalmers University of Technology, Sweden. In 2006, he was with Laboratory of Electromagnetics and Acoustics, Swiss Federal Institute of Technology, Lausanne, Switzerland. From 2007 to early 2008 he was with Laboratory of Photonics and Microwave Engineering at Royal Institute of Technology, Stockholm, Sweden. Since December 2009 he has been with Antenna Research, Analysis, and Measurement Laboratory at University of California, Los Angeles as a visiting PhD student. His research interests include design and characterization of multi-element antennas in multipath environments, design of high-performance waveguides for fast optical modulators, active and passive microwave circuit design, computational elecromagnetics and antenna theory.