Investigation on 10 m Semi Anechoic Chamber by Using Grid-Ferrite and Open-Top Hollow Pyramidal EM Wave Absorber

摘要

This paper investigates the 10m semi anechoic chamber using a new type hybrid EM wave absorber consisted of the grid-ferrite and the open-top hollow pyramidal EM wave absorber. We designed a new type hybrid EM wave absorber, which length could be slightly realized 65cm. The 10m semi anechoic chamber was constructed in the size of L21.5 m x W13.5 m x H8.9 m as the result of the ray-tracing simulation using this absorber. Then, the site attenuation in the constructed anechoic chamber was measured by using the broadband calculable dipole antennas. As the result, the maximum deviations between the measured site attenuation and theoretical calculated one were obtained within ±3.6 dB in the frequency range of 30 MHz to 300 MHz. It was confirmed the validity of a new type hybrid EM wave absorber. Moreover, it was confirmed that the measured results agree with the ray-tracing simulation results, in which the differences are about ±1.5 dB.