Surface acoustic wave device with an angle alpha related to specific piezoelectric substrates

摘要

A surface acoustic wave device includes a piezoelectric substrate and plural IDTs for sending and receiving SAW mounted on the substrate. At least one of the IDTs includes a positive electrode including plural positive split electrodes (PSEs) and a negative electrode including plural negative split electrodes (NSEs). The PSEs and NSEs are arranged alternately. Each of the PSEs andNSEs has apair of electrode fingers. Two electrode fingers of each of the split electrodes are different in width in a direction in which a SAW is excited. An angle alpha determined by a direction transverse to the electrode fingers from one of the two electrode fingers having a smaller reflection factor toward the other one having a larger reflection factor and a direction in which the SAW excited by the IDT including the split electrodes travels to one of the IDTs for receiving the SAW is equal to or larger than 0 DEG and smaller than 90 DEG , i.e., 0