Contactless Antenna Gain Pattern Estimation From Backscattering Coefficient Measurement Performed Within Reverberation Chambers

This paper presents the antenna gain pattern estimation from backscattering coefficient measurement performed within a reverberation chamber (RC). The antenna backscattering coefficient is measured for two load conditions, namely an open circuit and a 50 Ω load, enabling to distinguish the radiation and structural modes from the total backscattered field. This approach is applied to the measurement of the gain pattern of a Vivaldi antenna at 6.5 GHz and compared to a conventional transmission-type measurement within an anechoic chamber. The main lobe of the radiation pattern is in good agreement between both measurements. The difference between maximal gains, retrieved after a reference measurement using a metallic plate, is equal to 0.04 dB. A second validation is performed using a log-periodic antenna at 3.5 GHz, showing less than 0.76 dB difference over the measured angular range. To the author's knowledge, this is the first time that a contactless gain pattern measurement is performed and validated within an RC.