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

In a previous paper we have presented a method for evaluating the performance of anechoic chambers by analyzing the Sparameters of a system comprising two antennas facing each other in an anechoic chamber using the matrix pencil method. In this work, we present an improvement of this resonance detection technique using only the transmission parameter S21. The propagating components of the transmission parameter S21 are derived over small frequency intervals using the matrix pencil method and then removed from S21 in a two-level decomposition procedure. The resonances are clearly identified from the residual signal. Two examples of resonance detection in two different anechoic chambers illustrate the proposed method