Wideband frequency-domain material characterization up to 500 GHz

A compact quasioptical setup is designed and optimized for material characterization in the frequency range 50 GHz to 500 GHz. The S-parameters are measured with a commercial Vector Network Analyzer (VNA) together with its mm/sub-mm frequency extenders. A simple practical calibration process is used to determine the diffracted waves on the material surface. A new method is proposed to extract the complex permittivity of the material under closed-form formulas which can help for a parametric error analysis. Several material slabs are measured and the results are presented and analyzed.