An NRD guide excited millimeter wave narrow bandpass filter using whispering gallery mode high-Q resonators

We focused on an NRD guide and the Whispering Gallery (WG) mode high Q sapphire resonator which have the excellent low loss characteristics in millimeter wave region. In this paper, the NRD guide excited millimeter wave narrow bandpass filter using WG mode sapphire resonators was designed and fabricated. As a result, it was reali%ed that the 3-pole bandpass filter with center frequency 58.64GH% and 3dB bandwidth 273MH%. Moreover, its insertion loss was found to be about 1.5dB.