FDTD SIMULATIONS FOR FAR-FIELD RANGE EVALUATION

摘要

The free-space VSWR technique, which involves scanning a field probe through the quiet zone area and plotting the amplitude and phase ripples over this region, is generally used for evaluating the performance of a far-field range. In this paper, this free-space VSWR technique is simulated by the finite-difference time-domain (FDTD) method to demonstrate the relationship between the ripple amplitude and the absorber reflectivity. The commercial package named "FIDELITY~(TM)", based on FDTD algorithm released by Zeland Software, Inc., is used for the simulations. The pyramidal absorbers on the walls of the far-field range are modeled by using effective layer model. That is, in the FIDELITY~(TM) simulation setup, the absorbers are replaced with several homogeneous but uniaxially anisotropic layers. The amplitude ripples for both cases of 12-in-pyramid chamber and 18-in-pyramid chamber are presented and discussed.