Characterization of complex permittivity properties of materials in rectangular waveguides using a hybrid iterative method

In many microwave applications, an accurate knowledge of the complex permittivity properties of materials is usually required. A new procedure for the accurate determination of these properties is presented, based on an optimization algorithm that makes use of measured scattering parameters and simulated results of a cylindrical rod of dielectric material passing completely through a rectangular waveguide. The simulation tool employed consists of a very accurate hybrid iterative method. Results for the permittivity properties of ethanol (high-loss liquid material) are presented and validated with results from the literature.