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

摘要

A SAW resonator includes an IDT electrode formed on a piezoelectric substrate and reflector electrodes disposed on both sides of the IDT electrode. The IDT electrode includes first finger-electrodes, second finger-electrodes and strip-line electrodes. 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.