Title:
SURFACE ACOUSTIC WAVE FILTER
Document Type and Number:
Japanese Patent JP3348824
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To miniaturize a filter and to maintain a guarantee attenuation characteristic by arranging comb-like capacitive electrodes in the same length as a reflector formed in a vertical direction against the cross direction of comb-like electrodes constituting exciting electrodes at the maximum in the respective positions of the reflector electrodes facing the connection points of a surface acoustic filter.
SOLUTION: Surface acoustic wave resonators where the exciting electrodes 2 are arranged on piezoelectric substrates and the reflector electrodes 3 on both sides are oppositely arranged so as to constitute the surface acoustic filter 5. The capacitive electrodes 4 having the same lengths as the reflector electrodes at the maximum are arranged on the piezoelectric substrates positioned on the outer side of the reflector electrodes 3 of the surface acoustic wave filter 5 constituted of the input side surface acoustic wave resonator and the output side surface acoustic wave resonator. The capacitive electrodes 4 are formed in the vertical direction against the cross direction of the comb-like electrodes 12 of the exciting electrode 2 constituting the input side surface acoustic wave resonator and the output side surface acoustic wave resonator and they form more than a pair of comb forms. Then, electrode capacity which reduces when the surface acoustic wave filter 5 is miniaturized is secured.
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Inventors:
Mitsuhiko Negishi
Hiroyuki Amano
Hiroyuki Amano
Application Number:
JP28302297A
Publication Date:
November 20, 2002
Filing Date:
September 30, 1997
Export Citation:
Assignee:
Kinseki Co., Ltd.
International Classes:
H03H9/145; H03H9/25; H03H9/64; (IPC1-7): H03H9/145; H03H9/25; H03H9/64
Domestic Patent References:
| JP3222511A | ||||
| JP8237059A | ||||
| JP555855A | ||||
| JP774588A | ||||
| JP6468114A |