적층형 전파흡수체의 설계 및 제작에 관한 연구

Abstract

With the progress of the electronics industry and radio communication technology, humans enjoy greater freedom in communication. On the other hand, certain problems, such as electromagnetic interference (EMI) and electromagnetic susceptibility (EMS), have arisen due to the increased use of electromagnetic waves. Therefore, finding a countermeasure against unwanted electromagnetic waves has become very important, along with finding the measurements of EMI and EMS. International organizations such as CISPR, FCC, ANSI, etc. have provided the standard for the electromagnetic (EM) wave environment and the countermeasure of electromagnetic compatibility (EMC).

An important application of absorbers is for the construction of an anechoic chamber. EM wave absorbers for anechoic chambers need broad-band absorption characteristics. In order to satisfy the international standards of anechoic chambers for EMI and EMS measurement, the absorption characteristics of absorbers must be higher than 20 dB over the frequency band from 30 MHz to 1 GHz. Since November 1998, however, the CISPR11 has required that the frequency bandwidth to be measured should be extended from 1 GHz to 18 GHz additionally. Since the tile ferrite EM wave absorber has an absorption frequency band from 30 MHz to 400 MHz, and the grid ferrite has an absorption frequency band from 30 MHz to 870 MHz, a new EM wave absorber with more wide-band characteristics is needed. Therefore, in this paper, an EM wave absorber with super wide-band frequency characteristics was proposed and designed in order to satisfy the above requirements by using the EMCM.

As a result, the proposed absorber has absorption characteristics higher than 20 dB over the frequency band from 30 MHz to more than 20 GHz. Furthermore, simulation has been carried out using FDTD method instead of the EMCM for improving the accuracy.