LONGITUDINALLY COUPLED RESONATOR TYPE SURFACE ACOUSTIC WAVE FILTER DEVICE

摘要

There is provided a longitudinally coupled resonator type surface acoustic wave filter device capable of obtaining a steep attenuation characteristic on the high-frequency side of a passband by increasing an attenuation amount on the high-frequency side of the passband and also capable of being configured so as to have a balance-unbalance conversion function. The longitudinally coupled resonator type surface acoustic wave filter device has a plurality of IDT electrodes (16, 17) disposed along an acoustic wave propagation direction, wherein a phase inversion portion (26) is provided that connects adjacent electrode fingers (26a, 26b) to the same voltage level at at least one part of at least one IDT electrode (16) among the plurality of IDT electrodes (16, 17).