| 摘要 |
A rectangular block of piezoelectric material serves as a filter for electric signals, presenting series resonance at a selected frequency between a pair of terminals. The block has a length and height substantially greater than its thickness and is poled in the direction of the thickness. A pair of electrodes on opposing faces of the block are coupled respectively to the terminals for developing a signal field transverse to the thickness direction and, in response to which, shear waves are propagated in the block. The thickness is one-half the shear wavelength. To prevent the development of spurious wave modes, the ratio of the height to the thickness is an odd integer.
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