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Anechoic Chamber Reflectivity Analyses below its minimal frequency using the Matrix Pencil Method

This paper investigates the propagation performances (reflectivity) of anechoic environment beyond its qualified frequency range. These analyses are conducted in the 50 MHz - 100 MHz frequency band inside the CEA-Leti and CNES anechoic chambers, whose minimal operating frequency starts at 100 MHz and 400 MHz respectively. To perform these studies a receiving antenna spatially sample a disk area or over the longitudinal axis centered on the quiet zone. Localization algorithms are used to identify major contributing paths to the chamber reflectivity for various antenna configurations. In the present work, the identification process is based on the Matrix Pencil Method (MPM) applied to uniform linear arrays decomposing the received field into planar waves expected from the transmitting antenna and the chamber response. Ad-hoc full wave simulations are used to correlate observations made from the measurements.