SURFACE ACOUSTIC WAVE DEVICE

摘要

A surface acoustic wave branching filter is provided in which the steepness of the filter characteristic at the high-frequency side of the passband of a first filter having a relatively low passband and the steepness of the filter characteristic at the low-frequency side of the passband of a second filter having a relatively high passband are increased. A surface acoustic wave branching filter 1 includes a first filter 11 and a second filter 12 each including a plurality of surface acoustic wave resonators to form a ladder circuit configuration. The first filter 11 in which the frequency range of the passband is relatively low is provided on a first piezoelectric substrate 13, and the second filter 12 in which the frequency range of the passband is relatively high is provided on a second piezoelectric substrate 14. The first piezoelectric substrate 13 and the second piezoelectric substrate 14 are rotation Y-cut X-propagation LiTaO 3 substrates, and the cut angle of the first piezoelectric substrate 13 is larger than the cut angle of the second piezoelectric substrate 14.