Novel evaluation method for complex high permittivity of BaTiO3 families at microwave frequency

A simple but practically accurate evaluation technique is proposed for the complex dielectric constant of high permittivity materials in microwave region using the discontinuity structure in coaxial line. The test fixture is designed using the accurate theoretical analysis, i.e., the extended spectral domain approach and mode matching method (ESDMM). The complex permittivity is estimated by inversely fitting the measured S-parameters of test fixture loaded with specimen to the most probable permittivity values of specimen using ESDMM simulation. The new method provides an easy way to evaluate the high complex permittivity exceeding 10,000, which is difficult to be measured by currently used measurement techniques.