SURFACE ACOUSTIC WAVE FILTER DEVICE AND UNIDIRECTIONAL CONVERTER TO BE USED FOR THE DEVICE

摘要

PROBLEM TO BE SOLVED: To constitute a wide-band surface acoustic wave filter deice capable of reducing an insertion loss remarkably. SOLUTION: An input-side converter 21 has group of the first pairs consisting of the plural first pairs having interdigital positive electrodes and interdigital negative electrodes where inter-center distances between with the first interdigit of the first short-circuit type floating electrode are respectivelyλ/6 andλ/3 and the group of the second pairs consisting of the plural second pairs having interdigital positive electrodes and interdigital negative electrodes where inter- center distances between with the second transducer finger of the second short- circuit type floating electrode are respectivelyλ/6 andλ/3.