| 摘要 |
PROBLEM TO BE SOLVED: To minimize the length of a wire to prevent a contact between the wire and an electrode, etc., and to improve the reliability of a surface acoustic wave filter by grounding the upper right and lower left reflectors of each of surface acoustic wave filters which are vertically connected in series on two stages after separating the reflectors from the bus bars connected to the upper and lower interdigital electrodes respectively. SOLUTION: The common bus bars 11 and 16 are held between the interdigital electrodes 12 and 17 on a piezoelectric substrate, and the electrodes 12 and 17 are held between the reflectors 13, 14 and 18, 19. With such a constitution, a surface acoustic wave filter is formed. The input and output sides of electrodes 12 and 17 are connected to an input terminal 20a and an output terminal 20c, and only the reflector 13 of the input side is connected to the bar 11 with the reflector 14 separated form the bar 11. In the same way, only the reflector 19 of the output side is connected to the bar 16 with the reflector 18 separated from the bar 16. The reflectors 13, 18 and 19, 14 are connected to each other and then connected to the ground terminals 20b and 20d respectively. As a result, a wire is shortened to easily prevent its contact to an electrode, etc., and the reliability of the surface acoustic wave filter is improved.
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