Nondestructive Electrical Characterization of Materials at Microwave Frequencies

本研究旨在开发合适的测量方法和相关的计算机软件，用于UHF和微波频率下材料复介电常数的无损表征。一根开放式的同轴线将被用来测量介电常数。一个固定的变分公式的孔径阻抗的同轴开口在一个地平面将被用来联系其输入反射系数与样品介质的电学性质。首先，将考虑大样本介质。薄介电片材料将在后面讨论。傅里叶变换方法将用于解决薄介质材料的情况，并考虑表面波激发的可能性。

This research is directed towards developing suitable measurement methods and related computer software for nondestructive characterization of the complex permittivity of materials at UHF and microwave frequencies. An open-ended coaxial line will be used to make permittivity measurements. A stationary variational formulation for the aperture impedance of the coaxial opening on a ground plane will be used to relate its input reflection coefficient with the electrical properties of the sample medium. To start with, large sample media will be considered. Thin dielectric sheet materials will be considered later. The fourier transform method will be used to solve the case of thin dielectric sheet materials, and possibilities of the surface wave excitation will be considered.