A study on the design of EM wave absorptive structure and its application for WCDMA band

In this paper, a new approach to implement a compact fully anechoic chamber using an absorbing structure based on a periodic structure is proposed. A simple electromagnetic wave absorber based on a periodic structure to substitute a pyramidal absorber in a conventional compact anechoic chamber is proposed and the results of applying it are demonstrated. The proposed absorbing structure shows a broadband reflectivity response with a fractional bandwidth of approximately 91% below -10 dB. As a result, the measured results show that the reflection loss in a compact fully anechoic chamber consisting of the proposed absorber is fairly uniform and it is definitely lower than in the shielded room without the absorber. Also, radiation characteristics of a dipole antenna measured in the chamber reveal that those are closed to the conventional results. This compact anechoic chamber can be utilized as a measurement facility for measuring the characteristics of WCDMA antennas.