TUNABLE FILTER

摘要

A tunable filter using Love waves includes an inductance for band extension connected to each of piezoelectric resonators, variable capacitances are connected to the piezoelectric resonator, the piezoelectric resonators each include a LiNbO3 substrate and an IDT electrode, and a pass band and an attenuation region are positioned in a frequency region on a lower frequency side relative to a value obtained by a calculation in which an acoustic velocity of a low-velocity transversal wave propagating in the LiNbO3 substrate is divided by a wave length defined by a period of the IDT electrode.

主权项

1. A tunable filter comprising:
a piezoelectric resonator; an inductance for band extension connected to the piezoelectric resonator; and a variable capacitance connected to the piezoelectric resonator; wherein the tunable filter uses Love waves; the piezoelectric resonator includes a LiNbO3 substrate and an IDT electrode provided on the LiNbO3 substrate; and a pass band and an attenuation region are present in a frequency region on a lower frequency side relative to a value obtained by a calculation in which an acoustic velocity of a low-velocity transversal wave propagating in the LiNbO3 substrate is divided by a wave length defined by a period of the IDT electrode.