Hybrid of periodic dyadic Green´s function and FEM for quiet zone analysis in anechoic chamber

Quiet zone is a region in the anechoic chamber where the reflexivity is controlled at a designed level. Analytical formulation and hybrid methods are implemented to analyze the quiet zone in an anechoic chamber, since it is difficult to simulate the whole chamber with periodic absorber arrays. Herein the reflection from a single absorber is operated with FEM while the reflection from absorbing walls and metal ground are operated with periodic dyadic Green´s functions (DGF). It describes the reflection from the periodic array absorbers as equivalent source to build the scatter field in the chamber, with floquent wave (FW) method taken to deal with the phase difference of the scatter field. The program of calculating the reflective field of any point in the chamber is given. The test procedure is described concisely for the comparison of simulation result and practical test