Efficient detection of resonances in anechoic chambers using the matrix pencil method

In a previous paper, we have presented a method for evaluating the performa nce of anechoic chambers by analyzing the S-parameters of a system comprisi ng two antennas facing each other in an anechoic chamber using the matrix p encil method. In this work, we present an improvement of this resonance det ection technique using only the transmission parameter S-21. The propagatin g components of the transmission parameter S-21 are derived over small freq uency intervals using the matrix pencil method and then removed from S-21 i n a two-level decomposition procedure. The resonances are clearly identifie d from the residual signal. Two examples of resonance detection in two diff erent anechoic chambers illustrate the proposed method.