An analysis of coupled Whispering Gallery mode resonator and its application to millimeter wave filter

The millimeter wave filter using two Whispering Gallery mode dielectric disk resonators is presented in this paper. Coupling coefficients of the dual disk resonator and external Q value of the single resonator excited by a dielectric waveguide are investigated theoretically and experimentally. A 2-stage bandpass filter has designed at the center frequency of 69.85GHz with bandwidth of 500MHz. An experimental result is well agreed to theoretical one with low-loss property of 1.8dB insertion loss.