Birch, Stewart, Kolasch & Birch
Acoustic surface wave device
 An acoustic surface wave device comprises transducers including interdigital electrodes formed on the surface of a piezoelectric material substrate of ceramic such as PZT, or a single crystal of such as LiNbO.sub.3 or a piezoelectric thin film of such as ZnO, wherein an electrical signal is converted into an acoustic surface wave and vice versa. The interdigital electrodes have been changed of the overlapping lengths of the adjacent electrode fingers that are overlapped with each other in accordance with a weighting function determined by a desired pass characteristic. A portion of the transducer region where an undesired acoustic surface wave is propagated, i.e. the portion outside of the envelope of the interdigital electrodes determined by the weighting function, is provided with an acoustic surface wave absorbing material such as silicon rubber. In a certain example, dummy electrodes may be provided between the electrode fingers of the interdigital electrodes. 
Murata Manufacturing Co., Ltd.
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inventional inventional inventional
Atsushi Hiromichi Kenji
Inoue Yamada Suzuki