Best Practices in Measuring the Quality Factor of a Reverberation Chamber

Abstract

Measurement of the quality factor of a reverberation chamber has been examined using numerical simulation and experimental measurements. The numerical simulations demonstrate that common frequency-domain and time-domain approaches yield the same measured quality factors, provided that the measurement bandwidths of each approach are equal and the frequency-domain measurements are accurately compensated for antenna-efficiency effects. Measurements performed using intentionally mismatched antennas eliminate the antenna loading effects and give the quality factor of the chamber itself. The experimental validation confirms that the frequency-domain and time-domain approaches yield the same measured quality factors under practical conditions when the antennas are well-to-moderately matched. However, the accuracy of the frequency-domain measurement is compromised when large antenna-efficiency compensation must be applied when using poorly matched test antennas. The narrowband time-domain approach with poorly matched antennas provides consistent and repeatable measurements of the quality factor of the chamber itself without antenna loading effects.