Dielectric resonator, dielectric filter, dielectric duplexer, communication device, and method of producing dielectric resonator

A dielectric filter comprising a shield cavity with conductive properties, a dielectric resonator, and an external coupling which electromagnetically couples to the dielectric resonator,

• said dielectric resonator including a substantially columnar dielectric having a resonant region adapted for resonance at a frequency arranged in the shield cavity, a thin film multi-layer electrode formed on at least one of two faces opposite to each other of the dielectric, and a concave portion formed substantially evenly around the peripheral side face of the resonant region of the dielectric.

A dielectric duplexer comprising:

• a shield cavity with electroconductive properties,
• a dielectric resonator, an external coupling which electromagnetically coupled to the dielectric resonator, and an input-output connection which is connected to the external coupling and to an antenna connection,
• said dielectric resonator including a substantially columnar dielectric having a resonant region adapted for resonance at a frequency arranged in the shield cavity, a thin film multi-layer electrode formed on at least one of two faces opposite to each other of the dielectric, and a concave portion formed substantially evenly around the peripheral side face of the resonant region of the dielectric.

A communication device comprising

• a dielectric duplexer, one of a transmission circuit and a receiving circuit connected to the dielectric duplexer,
• said dielectric duplexer including a shield cavity with conductive properties, a dielectric resonator, an external coupling which electromagnetically couples to the dielectric resonator, an input-output connection connected to the external coupling and to an antenna connection,
• said dielectric resonator including a substantially columnar dielectric having a resonant region adapted for resonance at a frequency arranged in the shield cavity, a thin film multi-layer electrode formed on at least one of two faces opposite to each other of the dielectric, and a concave portion formed substantially evenly around the peripheral side-face of the resonant region of the resonator.

A method of producing a dielectric resonator which comprises the steps of:

• forming a thin film multi-layer electrode on at least one of two faces opposite to each other of a substantially columnar dielectric and an electrode on the other face to define a resonant region between said electrodes,
• fixing said dielectric to a rotation apparatus, and
• rotating said dielectric to cut substantially evenly the dielectric around the peripheral side-face of the resonant region thereof with a cutter.