# Publication Citation: Early-time Behavior in Reverberation Chambers and Its Effect on the Relationships Between Coherence Bandwidth, Chamber Decay Time, RMS Delay Spread, and the Chamber Build-up Time

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Author(s): Christopher L. Holloway; Haider Shah; Ryan J. Pirkl; Catherine A. Remley; David A. Hill; John M. Ladbury; Early-time Behavior in Reverberation Chambers and Its Effect on the Relationships Between Coherence Bandwidth, Chamber Decay Time, RMS Delay Spread, and the Chamber Build-up Time August 12, 2012 The use of reverberation chambers for electromagnetic testing is widely being accepted for use in many measurement applications. In recent years reverberation chambers are beginning to merge as a test facility for testing wireless device and for emulating different wireless multipath environments. The commonly used quantities for characterizing the chambers in wireless applications are, (1) the chamber quality factor, (2) the chamber decay time , (3) RMS delay spread of the time-domain chamber response, and (4) the coherence bandwidth of the frequency-domain transfer function of the chamber (BW). Analytic expressions that relate RC and BW and the relationship between {rms} and BW are given in the literature. However, these expressions neglect the early-time behavior of the chamber, and hence give inconsistence results when analyzing experimental data. In this paper we discuss the relationship between BW, RC, and $\tau_{rms}$ for realistic chamber behaviors, and we present expressions for these relationships when one takes into account the early-time behavior of the reverberation chamber. This early-time behavior is imperative (or crucial) when one tries to assess and compare these different quantities in experimental data and as we will see, the relationship between these quantities can be different for different chambers (i.e., different chamber sizes and loadings). The model presented here illustrates the how the early-time behavior can effects these chamber characteristic quantities for loaded and unloaded chambers, and illustrate the problems that can occur when the early-time behavior is not considered. IEEE Transactions on Electromagnetic Compatibility build-up time,coherence bandwidth,chamber decay time,early-time behavior,reverberation chambers,rms delay spread,wireless propagation environments Electromagnetics Click here to retrieve PDF version of paper (1MB)