Surface acoustic wave (SAW) resonator, SAW filter and SAW antenna duplexer using the SAW resonator

摘要

A SAW resonator includes an IDT electrode (13) formed on a piezoelectric substrate and reflector electrodes (14,15) disposed on both sides of the IDT electrode. The IDT electrode includes first finger-electrodes (132), second finger-electrodes (134) and strip-line electrodes (135). The first and the second finger-electrodes do not overlap with each other but are acoustically coupled together by the strip-line electrodes. This acoustic coupling by the strip-line electrodes eliminates the need for a common bus-bar electrode, so that the loss caused by the resistance of the common bus-bar electrode can be reduced, and the SAW resonator can be downsized.