Waveguide measurement technique for complex permittivity of materials with high or low losses

A novel evaluation method for variety of the dielectric materials with low or high losses is reported. The proposed evaluation method is based on the hybrid numerical method [1] combining the extended spectral domain approach with mode-matching method. This does not include any approximation unlike in the case of the perturbation scheme. The sample may be a columnar structure with the arbitrarily cross section and electrically large or small, and it is placed at arbitrarily position in the waveguide. The size of sample is chosen properly so as to achieve the adequate accuracy of the scattering parameters S₂₁ measurements with TE₀₁ mode. For example, the smaller sample should be prepared for the material with high permittivity and/or high loss and it should be placed near to the waveguide wall where the electric field is weaker than in the center for TE₀₁ mode.