Spatial Characterization of Multi-element Antennas
Licentiatavhandling, 2011

The overall goal of the current thesis is to establish some bases for understanding and characterization of multi-port antennas in a rich multipath environment. Multi-port antennas are the inevitable keystone of multiple input and multiple output wireless communication systems. Due to multidisciplinary nature of the applications of multi-element antennas, they are the subjects of many research groups worldwide resulting in inconsistent nomenclature among them. In this thesis, much effort is expended to look upon this realm of engineering in a unifying approach, with the major stress on electromagnetic aspects of this area. The thesis throws light upon different significant parameters as the key-gauges for characterization of multi-port antennas. We illustrate the dependency of precise measurement of diversity gains upon total number of independent measured samples. Two closed-form formulas are devised rendering diversity gains of two-port antennas in a rich scattering environment. Some examples are presented to verify the accuracy of these formulas. Moreover, received signals at different ports of a multi-element antenna in a multipath environment are the major sources for its assessment. There are certain functions governing the relation between the received signals at different ports of a radiation system and an arbitrary incident electromagnetic wave. The precise derivation of these formulas for different cases of interest are presented in this thesis. Furthermore, it has been frequently acknowledged that in a uniform rich multipath environment the beam-forming technique does not prove beneficial. Here for the first time, we stress that in a uniform non-rich scattering environment, beam-forming technique bestows considerable gain. We demonstrate that the achieved gain in respect to a similar radiation system reduces as the multipath environment becomes richer. In addition to that, it is known that reverberation chambers are the contemporary measurement tools for antenna systems to be used in scattering environments. The shape of these measurement tools plays a significant role in their ultimate performance. We show that rectangular reverberation chambers prove to be more advantageous compared with their cylindrical and spherical counterparts.

EB room
Opponent: Adj. Prof. Anders Sunesson

Författare

Nima Jamaly

Chalmers, Signaler och system

Effect of Mutual Coupling and Human Body on MIMO Performances

2009 Proceedings of the Third European Conference on Antenna and Propagation, EuCAP,; (2009)p. 1042-1046

Paper i proceeding

Compact Formulas for Diversity Gain of Two-Port Antennas

IEEE Antennas and Wireless Propagation Letters,; Vol. 9(2010)p. 970-973

Artikel i övriga tidskrifter

Performance of directive multi-element antennas versus multi-beam arrays in MIMO communication systems

EuCAP 2010 Fourth European Conference on Antennas and Propagation, Barcelona, 12-16 April 2010,; (2010)

Paper i proceeding

Mode densities in rectangular, cylindrical and spherical cavities in application to the reverberation chamber

IEEE Transactions on Electromagnetic Compatibility,; Vol. 51(2009)p. 1044-1046

Artikel i vetenskaplig tidskrift

Study of Excitation on Beam Ports versus Element Ports in Performance Evaluation of Diversity and MIMO Arrays

3rd European Conference on Antennas and Propagation, EuCAP 2009; Berlin; Germany; 23 March 2009 through 27 March 2009,; (2009)p. 1753-1757

Paper i proceeding

Styrkeområden

Informations- och kommunikationsteknik

Ämneskategorier

Elektroteknik och elektronik

R - Department of Signals and Systems, Chalmers University of Technology

EB room

Opponent: Adj. Prof. Anders Sunesson