BULK ACOUSTIC WAVE RESONATOR

摘要

PURPOSE: A bulk acoustic resonator including phase differences is provided to increase electric acoustic coupling factor by reducing loss generated by an acoustic wave of a vertical direction. CONSTITUTION: A bulk acoustic resonator comprises an air joint (270), a bulk acoustic resonation unit (260), and a reflection layer (220). The air joint is located on a circuit board (210). The bulk acoustic resonation unit comprises a first electrode (230), a second electrode (250), and a piezoelectric layer (240) located between the first electrode and the second electrode. The reflection layer reflects the wave of a resonance frequency generated in the piezoelectric layer based on a signal applied to the first electrode and the second electrode located at the bottom of the bulk acoustic resonation unit.