Precise Measurement of Low Loss Dielectric Materials Using Quasi-optical cavity Technique

The method of Fabry-Perot quasi-optical cavity is one of the most accurate methods for the precision measurements of complex permittivity and loss tangent of low loss dielectric materials at millimeter wave frequencies. In our earlier work, a fixed operation frequency is employed for the cavity length variation technique. In recent years, with the increasingly high-precision request and the instrumentation progress in both hardware and software, the frequency variation technique has become commonly used in quasi-optical cavity system. In this paper, we describe some considerations in quasi-optical resonator test system designation, together with mode identity techniques and the measurement results of some materials.