Influence of through hole on liquid material's complex permittivity measurement using a rectangular waveguide and a dielectric tube

摘要

On the previously reported complex permittivity measurement method for the liquid phantom material using a dielectric tube piercing a rectangular waveguide, we study the influence of through hole of dielectric tube by comparing measurement results of deionized water. In this comparison, three types of dielectric tubes are used. The first one is fully made of dielectric material, the second is a dielectric tube joined with metal tubes on both ends, and the third is the one joined with metal pin-hole tubes on both ends. Besides, we built another measurement system based on waveguide S-parameter method to compare measured results of deionized water under the same condition. The experimental result shows that the proposed method gives the complex permittivity of deionized water closer to that measured by the waveguide S-parameter method, when the tube structure is closer to that of analysis model. It is also shown that both the real and imaginary parts of relative complex permittivity get smaller as the through hole becomes large.