Depolarized fields inside a magneto-dielectric sample interfere the accurate measurement by microwave cavity perturbation. These depolarized fields occur due to the polarization of test sample by the electromagnetic field, which also change its polarization value depending on the volume and shape of the sample. To characterize the dielectric sample more accurately, we proposed an advanced rectangular cavity perturbation method. In this method, we investigate the change in the resonant frequency and Q-factor of a cavity which depends on the volume, shape of the sample and depolarized fields within the sample. The coefficients for calculating the permittivity and permeability of the sample are derived by separating the uniform and depolarized fields within the sample when the sample is inserted in the cavity. These separation of fields plays an important role to improve measurement accuracy. The proposed unified rectangular cavity perturbation technique is validated initially by measuring the resonance frequency and quality factor and then calculating the complex permittivity and permeability at $TE_{10n}$ mode. The widely used reference dielectric material ($Al_2O_3$) and magnetic material (YIG) samples are measured with a vector network analyzer. The measurement was performed when the magneto-dielectric sample having various shapes and volumes inserted into the rectangular cavity resonator. In comparison with the previous cavity perturbation methods, the permittivity and permeability has been calculated more accurately with various shapes of the test sample. Based on the proposed method, we found that the maximum sample volume to the cavity for various samples can also increase about 40%. Therefore, the sample maximum volume ratio to the cavity has been expanded sufficiently than the classical method.
전자전기 공학에서 새로운 응용 연구를 위해 신 물질의 전자기적 특성, 즉 복소 유전율과 복수 투자율을 측정하는 것은 매우 중요하다. 물질의 전자기적 특성을 측정하기 위해 다양한 방법이 연구 중이지만, 가장 간단하고 정교한 물질측정법 중 하나는 cavity perturbation 기법이다. 본 논문에서는 cavity perturbation 기법을 기반으로, 필드에 영향을 받는 물질의 부피와 물질의 모양에 따라 변하는 분극화 필드를 수학적으로 분석하여 현재까지 제시된 물질 측정법보다 우수한 측정법을 제안하였다. 본 논문에서 제안하는 측정법을 이용하여 막대모양, 디스크모양, 정육면체 또는 구 모양의 물질을 대상으로 기존보다 정확한 측정 복소 유전율, 투자율 결과를 보였다. 이를 미래의 전자기 응용 연구에 신 물질 활용에 있어서, 정확한 물질 정보를 쉽고 간단하게 알아낼 수 있게 되었다.
