A New Low-Frequency Model of Absorber Array Founded by Transmission/Reflection Method

In order to predict performance of anechoic chamber with absorbers by simulation, an equivalent layer model of absorbing array should be needed, which can be carried out by homogenization. In this procedure, absorbing array is replaced by a uniform media with a effective electromagnetic properties in transverse direction, and divided a proper number of layers in longitudinal direction. In order to obtain the effective properties of each layer, a two-port network model of period cell based on transmission/reflection method (NRW)[3][6][7] will be founded. We will calculate effective properties through the scattering parameters on two ports, and then substitute each group of properties into corresponding layer model to get reflectivity. According to comparing the reflectivity among the model founded by NRW, the model by Hasin-shtrikman (HS) bound and the model of initial pyramid array, it can be proved that the method in this paper can get a better approximating result especially in low-frequency range (below 100 MHz).