| 摘要 |
PROBLEM TO BE SOLVED: To provide an end surface reflection type longitudinal-coupling surface acoustic wave filter which is small and has a desirable filter characteristic whose spuriousness out of passing band is efficiently suppressed. SOLUTION: The end surface reflection type longitudinal-coupling surface acoustic wave filter 1 has interdigital transducers 3, 4 formed on a piezoelectric substrate 2 reflecting a SH-type surface wave between two facing ends 2a and 2b. In the filter 1, a location of a spuriousness due to a distance between the two facing ends 2a and 2b is made close to an attenuation pole of frequency characteristic for the first and the second interdigital transducers 3, 4 to suppress the spuriousness due to the distance between the two facing ends. COPYRIGHT: (C)2004,JPO
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