Preliminary study of a reverberation chamber method for multiple-source testing using intermodulation

Abstract

The illumination of a system under test by multiple sources can lead to intermodulation (IM) effects that give rise to threat signals at the IM frequencies. The result of this is that the electromagnetic (EM) compatibility and signal integrity of that system may be compromised by two or more signals that are, individually, out of the frequency band of concern. As the EM environment continues to be increasingly polluted and electromagnetic compatibility (EMC) tests rely, predominantly, on a single-source illumination, this is an issue that is ripe for further investigation. The statistical nature of the reverberation chamber and its behaviour in isolating the test environment from the ambient (outside) environment indicates that this is a facility worth considering for multiple source (IM) testing. This study discusses the need for such an expansion in test methods, driven by an increasing interest in functional safety. It presents the results of a preliminary, simulation based, study of the reverberation chamber used with multiple sources. The purpose of this study is to demonstrate that the reverberation chamber can provide a facility where worst-case multiple-source EM interference effects can be tested. It concludes that the proposed approach has the potential to be viable and suggests experimental studies to confirm the behaviour and also to confirm that this approach can be used as an indirect method of reducing the lowest working frequency of the reverberation chamber.