Study of distributions of modes and plane waves in reverberation chambers for the characterization of antennas in a multipath environment

A rectangular metallic cavity is known to support a number of resonant cavi ty modes. Each of these modes can be described as a slim of eight plane wav es incident from different angles. This paper studies how these plane waves are angularly distributed in space, which is of interest when the cavity i s used to simulate multipath environment. The results show that the angular distribution in space is uniform provided that the three linear dimensions of the chamber are sufficiently large. and do not deviate too much from ea ch other. As an example, two rectangular cavities with dimensions 1 m x 0.8 m X 1 m and 5.5 m X 2.5 m X 3.5 m are analyzed in detail, and are shown to have uniform plane-wave distributions. We also demonstrate how the chamber geometry may he chosen in order to weight the angular plane-wave distribut ion in the elevation plane. A result of the study is that we defect a 25 MH z frequency band with very few modes in a small chamber designed fbr use wi th reduced accuracy in the GSM 900 MHz band. We also propose how this chamb er can be modified to obtain uniform mode distribution over this frequency band, (C) 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 30: 386-3 91, 2001.