Material Characterization Improvement in High Temperature Rectangular Waveguide Measurements

This research presents a method using modal analysis by which electromagnetic characterization of materials in a partially filled rectangular waveguide, having a single top air gap, can be accurately performed. Thermal expansion of waveguides commonly occurs during high-temperature measurements, resulting in air gaps between the sample and waveguide walls. Higher order modes are excited by the discontinuous geometry, which are not accounted for in most closed form extraction algorithms.