Longitudinal leaky Surface acoustic wave (LLSAW) device for e.g. radio frequency filter of e.g. mobile telephone, has dielectric sheet formed on surface of finger electrode portions and surface of substrate between electrode portions

摘要

The LLSAW device has a transducer (14) that includes interdigital electrodes (6A,6B) having finger electrode portions (3) on surface of a piezoelectric substrate (1). A surface acoustic wave is oscillated in longitudinal direction by the transducer. A dielectric sheet (5) is formed on surface of finger electrode portions and on the surface of piezoelectric substrate between the finger electrode portions. The transducer is made of aluminum and dielectric sheet is made of silicon oxide.