Using reverberation chambers for EM measurements

Reverberation chambers (RC) are being used for several decades. The main advantage is the high field strength which can be generated, with only modest power. In the last few years the use of RCs became much popular, for testing multi-path propagation for communication links, or testing the coupling of complex fields into transmission lines, as well as testing coupling into objects, and measuring the shielding effectiveness of materials. The costs for setting up a conventional RC, with rotating mode stirrers, is low compared to the cost of anechoic chambers. Existing chambers are making use of a paddle wheel to change the resonant modes in the chamber. A transportable reverberation chamber with varying angles between wall, floor and ceiling and with vibrating walls has been used for testing of many systems. Inside this Vibrating Intrinsic Reverberation Chamber (VIRC) a diffuse, statistically uniform electromagnetic field is created without the use of a mechanical, rotating, mode stirrer. This chamber results in a better homogeneity and increased field strength compared to conventional mode stirred reverberation chambers. The use of flexible material to build the VIRC is making a test facility at even lower cost possible. Furthermore such a VIRC can be built around a test object, and the test object is not to be moved to an anechoic chamber. This can reduce test costs for complex systems. The basic principles of RC and VIRC are explained, and several applications shown.