| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface acoustic wave filter in which chip size can be reduced, degradation of attenuation characteristics can be prevented, and good frequency characteristics can be achieved.SOLUTION: In a longitudinal coupling double mode surface acoustic wave filter, an input side filter 10 and an output side filter 20 which have a plurality of IDT electrodes are formed with a connection area therebetween, on a piezoelectric substrate. In the surface acoustic wave filter, a plurality of electrode finger pieces of the IDT electrode are arranged in a first electrode pitch, grating electrodes 18 and 19 consisting of a plurality of electrodes are connected to both ends of an IDT electrode 12 respectively at the center among the IDT electrodes, the grating electrodes 18 and 19 are connected to the IDT electrode 12 at the center in the connection area and connected to ground terminals 17b and 17c formed in the side opposite to the connection area, and additionally, the electrodes are arranged in a second electrode pitch which is different from the first electrode pitch. |
