抄録
In this paper, the FDTD method has been applied to analyze the site attenuation of an anechoic chamber at 100 MHz or less where the ray tracing method is not applicable. To calculate site attenuation by a personal computer, the dipole antenna and the EM absorber were modeled by the large-cell which was larger than the diameter of antenna element and the thickness of EM absorber. The equivalent diameter of the antenna element was determined so that the calculated site attenuation in free space agreed with that by the method of moment, and the equivalent dielectric constant and permeability of the absorber were determined so that the reflection coefficient agreed with that by the transmission theory. The site attenuation of the compact anechoic chamber was calculated for frequencies from 30 MHz to 100 MHz and compared with the measured one to confirm the validity of the proposed modeling method. The results indicated that the deviation between the calculated values and the measured ones was within 2 dB.
