| 摘要 |
PURPOSE:To suppress influence of manufacture variation by reducing a diffraction loss by eliminating cross width among electrode fingers that corresponds to response of 6% in magnitude in comparison with the maximum response of impulse response. CONSTITUTION:The parts of electrode fingers that correspond to response of not less than 6% in comparison with the maximum response of impulse response are shown by dotted lines in the figure and parts between electrode fingers 11 and 12, 12 and 13, 13 and 14, 14 and 15, and 15 and 16 correspond to response of less than 6% in magnitude, where electrode fingers opposing mutually without crossing are provided at intervals. Between envelopes connecting finger tops of interdigital electrodes corresponding to impulse response, only the cross width of parts 17-27 of less than 6% in maximum response is made zero to eliminate excitation source of small cross width, so that a large diffraction loss caused by it will disappear. In addition, influence of variance in manufacture of electrode fingers of small cross width is eliminated and the difference between designed desired frequency characteristics and actual frequency characteristics can be reduced. |
