주파수 의존형 FDTD 법을 이용한 페라이트 코어 장착 선로의 해석

Abstract

The suppression of electromagnetic (EM) wave noise is required for the efficient operation of communication system. In order to suppress EM wave radiation, generally, electromagnetic absorber such as ferrite core or ferrite bead is employed, and the ferrite material has a frequency dispersion characteristic. FDTD is an efficient method to perform the EM wave analysis for the ferrite material. Up to date, however, EM wave analysis for the wire coated with the ferrite core by FDTD method reflecting the frequency dispersion characteristics of the permeability has not been reported .

In this thesis, in order to confirm the suppression of the EM wave noise by ferrite core, the EM wave analysis was performed for the wire surrounded with ferrite core by using the frequency-dependent FDTD method, where the frequency dispersion characteristics of the permeability of the ferrite were considered. Concretely, firstly, we theoretically evaluated the reflection coefficient for the plane wave perpendicularly incident on the ferrite material, and confirmed the validity of the frequency-dependent FDTD method by comparing the reflection coefficient calculated by the frequency-dependent FDTD method with theoretically evaluated one. In addition, near-field EM dispersion and the load impedance were investigated for the wire loop surrounded with ferrite core. As a results, it was found that the results calculated by the frequency-dependent FDTD method showed a good agreement with those theoretically evaluated, which reveals the validity of the frequency-dependent FDTD.