漆을 支持材로 使用한 多層形 電波吸收&#20307

Abstract

With the progress of electronics industry and radio communication technology, human being might enjoy its abundant life. On the other hand, serious social problems such as electromagnetic interference (EMI), have been arisen due to the increased use of electromagnetic (EM) waves. Therefore, International organizations such as CISPR, FCC, ANSI, have provided the standards for the EM wave environments and for countermeasure of the electromagnetic compatibility (EMC).

Generally, a silicone rubber and a chlorinated polyethylene(CPE) have been used as a binder for high-performance composite EM wave absorbers.

In this dissertation, the EM wave absorption performance of natural lacquer which is newly proposed as a binder was investigated. MnZn ferrite EM wave absorbers mixed with natural lacquer were prepared and their absorption ability was also investigated.

The EM wave absorbers are fabricated in different proportions of MnZn, or NiZn ferrite and natural lacquer, and their reflection coefficients are measured. The permittivity and permeability are calculated by using the measured reflection coefficients. The EM wave absorption abilities are calculated according to different thicknesses of the EM wave absorbers, and then multi-layer type EM wave absorbers with broad bandwidth are calculated and fabricated in accordance with different layer-sequence. The measured results are analyzed by comparing with the calculated ones.

As a result, the prepared MnZn ferrite EM wave absorbers which are mixed with natural lacquer showed excellent EM wave absorption characteristics compared with MnZn ferrite EM wave absorbers which are mixed with the conventional binders, such as a silicone rubber and a chlorinated polyethylene(CPE). The measured results of the single-layered type EM wave absorbers are a function of thickness agree well with the simulated ones.

In addition, the measured results of the two-layered EM wave absorbers composed of MnZn Ferrite and NiZn Ferrite and fabricated with natural lacquer binders are similar with the simulated ones. Thus, it was shown that the multi-layered EM wave absorbers have more broadband characteristics than the single-layered ones.