Reflectivity Characterization and Identification of Primary Reflection Path in Anechoic Chamber Analysis

This paper presents an analysis of the reflectivity performance of the anechoic chamber. Measurements indicating the performance of the chamber-installed foam absorbers (described in a companion paper) are used to complete this analysis. This is followed by a comparison of the analysis results to chamber measurements taken in accordance with the free-space VSWR procedure [1]. Agreement between the analysis results and worst-case VSWR test measurements is within 1dB for a majority of reflection angles. In addition to chamber performance predictions, this paper describes a method of identifying primary reflection paths through interferometer calculations that compare all single bounce reflection path lengths to the direct path length. The angular spacing between interferometer nulls is used to identify the primary reflection direction. This information can be used to improve the overall chamber reflectivity by identifying areas of significant reflections and enhancing absorber treatments in these areas