Laminated dielectric filter, and antenna duplexer and communication equipment using the same
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsEmiko Kawahara, Toru Yamada, Hiroshi Kushitani, Hideaki Nakakubo
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Abstract
A laminated dielectric filter is formed by coupling a plurality of resonators to one another by electromagnetic-field coupling. In the laminated dielectric filter, a bypass circuit formed of a series circuit including bypass capacitors and transmission lines is provided in parallel to a magnetic-field bypass coupling between non-adjacent resonators. Thus, capacitance of the bypass capacitors can be regulated without being affected by the magnetic-field bypass coupling between the non-adjacent resonators. As a result, attenuation poles outside a passband can be controlled freely.
Claims2
An antenna duplexer, comprising a filter including a plurality of resonators, the resonators being coupled to one another by electromagnetic-field coupling,
- wherein non-adjacent resonators of said plurality of resonators are electrically coupled to each other with a bypass circuit formed of a bypass capacitor and a non-grounded transmission line, the bypass circuit functioning as a capacitive coupling parallel to a magnetic-field bypass coupling between non-adjacent resonators;
- wherein adjacent resonators of said plurality of resonators are electrically coupled to each other with a series circuit formed of an inter-stage capacitor and a transmission line, each series circuit functioning as a capacitive coupling parallel to a magnetic-field coupling between the adjacent resonators;
- wherein the plurality of resonators and the transmission line are formed inside a dielectric body;
- and
- wherein the filter is used as one of or both of filters on transmission and reception sides.
Communication equipment, comprising a filter including a plurality of resonators, the resonators being coupled to one another by electromagnetic-field coupling,
- wherein non-adjacent resonators of said plurality of resonators are electrically coupled to each other with a bypass circuit formed of a bypass capacitor and a non-grounded transmission line, the bypass circuit functioning as a capacitive coupling parallel to a magnetic-field bypass coupling between non-adjacent resonators;
- wherein adjacent resonators of said plurality of resonators are electrically coupled to each other with a series circuit formed of an inter-stage capacitor and a transmission line, each series circuit functioning as a capacitive coupling parallel to a magnetic-field coupling between the adjacent resonators;
- and
- wherein the plurality of resonators and the transmission line are formed inside a dielectric body.
Dependencies are inferred from the claim text.