PURPOSE: To provide the filter device whose side lobe characteristic is much more improved while the insertion loss is much reduced by applying an interval weighing method to a unidirectional transducer and providing a dummy electrode between an input side transducer and an output side transducer.
CONSTITUTION: An input side transducer 12 and an output side transducer 13 are respectively made up of a unidirectional transducer having a short-circuit type floating electrode and positive electrodes 14, 17, negative electrodes 15, 18 and the floating electrode are laid out based on the interval weighing method. Then dummy electrodes are respectively formed on an extension line of electrode fingers 14a, 14b of the positive electrode 14 of the input side transducer 12 and dummy electrodes 22a-22s are respectively formed on an extension line of electrode fingers 16a-16d of the floating electrode. The forming of the dummy electrodes above is similarly applied also to the output side transducer 13. Moreover, loss is reduced by forming dummy electrodes 25-28 acting like reflectors on other sides of the input side transducer 12 and the output side transducer 13 than sides to which the transducers are opposite.
| JPS60203012 | SURFACE ACOUSTIC WAVE DEVICE |
| JP3963081 | SURFACE WAVE DEVICE |
HORIO YASUBUMI
YAMANOUCHI KAZUHIKO
YAMANOCHI KAZUHIKO
| JPS616916A | 1986-01-13 | |||
| JPS5616313A | 1981-02-17 | |||
| JPH03133209A | 1991-06-06 |
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