| 摘要 |
PURPOSE: A SAW(Surface Acoustic Wave) filter is provided to be capable of obtaining a good frequency characteristic and securing a stable temperature coefficient. CONSTITUTION: Int the filter, an input IDT(302) formed at the upper portion of the piezoelectric substrate transforms an electrical signal into an acoustic wave signal. A multi-strip coupler(303) transmits the acoustic wave signal transformed from the input IDT after changing the direction of the acoustic wave signal. An output IDT(304) formed at the lower portion of the piezoelectric substrate corresponding to the input IDT transforms the acoustic wave signal transmitted from the multi-strip coupler into the electrical signal. And, the multi-strip coupler transforms the acoustic wave signal transmitted from the input IDT into a longitudinal wave signal. |
