Numerical modelling of diffraction of electromagnetic field on pyramidal radio-absorber on the side walls of the compact range.

Abstract

Abstract. Several issues concerning diffraction from pyramidal radio absorber that covers walls of a compact range are considered in this paper. In particular, differences in convergence and localization of higher order diffraction fields are demonstrated in comparison with those scattered on the back wall. In the case of the diffraction from the back wall, the incidence is almost normal to the wall, thus zeroorder field is significantly lower than higher-order reflected harmonics (-70 dB compared to -30 dB). In the case of the back wall, the angle of incidence can be very close to even 90 degrees, thus zero-order harmonic's amplitude becomes higher than amplitudes of high diffraction orders (-20 dB compared to -35 dB). However, the distribution of these fields in compact range's space is different: there are regions in which amplitudes of high diffraction orders are bigger than the amplitude of zero-