Balanced-type Circular Disk Resonator for Permittivity Measurements in the J-band

A J-band balanced-type circular disk resonator (BCDR) excited by 0.26 mm coaxial lines is developed to realize material characterizations over the entire J-band. The developed BCDR has WR3.4 waveguide interfaces with coaxial-to-waveguide converters, which allows for the selective excitation of the TM
0m0
modes in the resonator over a wideband. Owing to the mode selective behavior, the BCDR provides broadband material measurements of low-loss substrate materials. To demonstrate the developed resonator, the relative permittivities of cyclo-olefin polymer (COP) and perfluoroalkoxy alkanes (PFA) are measured in the J-band from 220 GHz to 330 GHz.