Time-domain Modeling, Characterization and Measurements of Anechoic and Semi-Anechoic Electromagnetic Test Chambers

Published

February 1, 2002

Author(s)

Christopher L. Holloway, Paul McKenna, Roger Dalke, Rod A. Perala, Charles Devor

Abstract

In this paper we present time-domain techniques for modeling, characterizing, and measuring anechoic and semi-anechoic chambers used for emission and immunity testing of digital devices. The finite-difference time-domain (FDTD) approach is used to model and characterize these chambers. In the FDTD model presented here we (1) discuss methods used to eliminate the need to spatially resolve the fine detail of the absorbing structures, (2) present a differential operator approach for incorporating both frequency-dependent permittivity and permeability into the time domain, and (3) discuss the effects of gaps and holes in ferrite tile absorbers on both absorber and chamber performance. Comparisons of the FDTD chamber model with measured data for different chamber sizes are presented. Finally, we discuss and illustrate how time-domain techniques can be used for chamber characterization, performance predictions, and diagnosing problems with both absorbers and chambers. With time- and frequency-domain techniques, we show how the performance of chambers can be significantly altered with only small chambers in the type of absorbing structure used, and we illustrate the undesirable modal field distribution that can occur inside a chamber if a non-optimal absorber is used.

Citation

IEEE Transactions on Electromagnetic Compatibility

Volume

44

Issue

1

Pub Type

Journals

Keywords

absorber and chamber performance, chamber modeling, FDTD, time-domain analysis, time-domain chamber diagnostics

Citation

Holloway, C. , McKenna, P. , Dalke, R. , Perala, R. and Devor, C. (2002), Time-domain Modeling, Characterization and Measurements of Anechoic and Semi-Anechoic Electromagnetic Test Chambers, IEEE Transactions on Electromagnetic Compatibility (Accessed October 7, 2025)