| 摘要 |
PROBLEM TO BE SOLVED: To improve filter characteristics in the case of use as a surface acoustic wave filter by simply increasing the attenuation in the side lobe of a normal electrode. SOLUTION: The plural pairs of input interdigital electrodes and the plural pairs of output interdigital electrodes are provided on the surface of a piezoelectric substrate for propagating surface acoustic waves. In this case, for the plural pairs of the interdigital electrodes or the plural pairs of the output interdigital electrodes, a pair each of interdigital electrodes 3 and 4 is additionally arranged separately for a distance controlled by a wavelength to both ends of the interdigital electrode provided with a prescribed pair number for which the width of one electrode finger 1, 2 and the interval of the electrode finger adjacent to it are respectively 1/8 wavelength and the respective additionally arranged interdigital electrodes are electrically connected with the plural pairs of the interdigital electrodes in a prescribed polarity.
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