Resonator device, filter, duplexer, and communication apparatus using the same

摘要

A multi-mode resonator device can be reduced in size even while increasing the number of resonators while including either a semi-coaxial resonator or a coaxial resonator. Coupling between a TEM mode as a resonance mode of the semi-coaxial resonator and a TM mode as another resonance mode can be facilitated, which enables coupling between the resonators at a predetermined coupling strength. Inside a cavity with a cover, a conductive rod and a dielectric core are disposed so as to substantially equalize a quasi-TEM-mode resonant frequency generated by the cavity and the conductive rod and a quasi-TM-mode resonant frequency generated by the cavity and the dielectric core. A coupling adjusting block is arranged at a place where the magnetic field of one of two coupling modes generated by the quasi-TEM and quasi-TM modes is strong and that of the other mode is weak. The invention also provides a filter, duplexer, and a communication apparatus using the resonator device.