Napenille IllinoisABsIllAcT A numerical method is presented that can be used to analyze an infinite array of pyramid absorben such as those used in anechoic chambers excited by a plane wave of arbitrary frequency and angle of incidence. The method can be adapted to any absorber geometry. The problem is solved using Transmission Line Matrix analysis (TLM) over a mesh placed around one absorber pyramid. Link voltages exiting the side of the single cell are delayed by a phase factor dependent upon the frequency and angle of incidence and re-inserted into the opposite side. This effectively simulates an infinite array of such absorbers. The method works because of the fact that the exciting signal looks the same everywhere (except for phase). The method yields gross reflection coefficient as a function of frequency and angle of incidence for any given absorber shape.