Dielectric resonator device, the coupling coefficient adjustment method and manufacturing apparatus

In a TM dual mode dielectric resonator apparatus, a cross-shaped TM dual mode dielectric resonator is provided in an electrically conductive case, and the TM dual mode dielectric resonator includes first and second dielectric resonators integrally formed so as to be perpendicular to each other, and there is further formed at least one coupling groove for coupling an operation mode of the first dielectric resonator with that mode of the second dielectric resonator, wherein the coupling groove is formed on at least one of front and back surfaces of a crossing portion of the first and second dielectric resonators, in a diagonal direction thereof so as to cut electric lines of force of either one of an odd mode and an even mode. Alternatively, at least one coupling projection may be formed in stead of the coupling groove.