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



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


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.
IEEE Transactions on Electromagnetic Compatibility


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


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 May 27, 2024)


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Created January 31, 2002, Updated October 12, 2021