Antenna Radiation Pattern Measurement in an Entirely Stirred VIRC Working as a (Quasi)-Chaotic Reverberation Chamber

Antenna radiation pattern measurements are traditionally performed in an anechoic environment trying to reproduce free space conditions. This article presents the proof-of-concept that such measurements can also be relatively easily performed in a reverberation chamber (RC), which could be assumed to be chaotic. Indeed, in such an environment, due to the cancellation of all the indirect unstirred paths, the only invariant path between the antenna under test (AUT) and the measuring one is the line-of-sight. Therefore, for a given angle of the radiation pattern, multiple acquisitions (i.e., for different stirring conditions) of the transmission coefficient between both antennas and their averaging is theoretically sufficient to extract the line-of-sight (LOS) from the stirred paths. The validity of such an approach is demonstrated from measurements performed between 1 and 25 GHz on two different sets of horn antennas in a low-cost suspended vibrating intrinsic reverberation chamber (VIRC) made of a metallized textile. As shown from these measurements and from an analytical theoretical model developed in this study, the accuracy of such measurements increases with the frequency and can be improved by inserting a few blocks of absorbers within the VIRC.