Whispering-Gallery Modes of Dielectric Structures: Applications to Millimeter-Wave Bandstop Filters

The purpose of this paper is to show the feasibility of millimeter-wave resonators utilizing whispering-gallery (WG) modes excited in planar and cylindrical dielectric structures. Measured resonant frequencies and quality factors in Ka- and W-bands are reported. Their applications to millimeter-wave integrated circuits are also dealt with. For this, a bandstop filter obtained by coupling two WG-mode dielectric resonators to a dielectric image guide is presented at about 35 GHz.