Acoustic resonator filter

An acoustic resonator filter comprising:

• a series portion of the acoustic resonator filter, the series portion including a plurality of series acoustic resonators electrically connected, in anti-series, between first and second ports of the acoustic resonator filter configured to pass a radio-frequency (RF) signal from the first port to the second port;
• a shunt portion of the acoustic resonator filter, the shunt portion including at least one shunt acoustic resonator electrically connected between one node of the series portion and a ground;
• and
• a DC voltage terminal configured to generate a DC voltage across at least one of the plurality of series acoustic resonators by an electrical connection of the DC voltage terminal to a first electrode of the at least one of the plurality of series acoustic resonators and to a different second electrode of the at least one of the plurality of series acoustic resonators.

An acoustic resonator comprising:

• a series portion of the acoustic resonator filter, the series portion including at least one series acoustic resonator electrically connected, in series, between first and second ports of the acoustic resonator filter configured to pass a radio-frequency (RF) signal from the first port to the second port;
• a shunt portion of the acoustic resonator filter, the shunt portion including a plurality of shunt acoustic resonators electrically connected to each other between one node of the series portion and a ground;
• and
• a DC voltage terminal configured to generate a DC voltage across at least one of the plurality of shunt acoustic resonators by an electrical connection of the DC voltage terminal to a first electrode of the at least one of the plurality of shunt acoustic resonators and to a different second electrode of the at least one of the plurality of shunt acoustic resonators, and
• wherein, with the DC voltage terminal configured to generates the DC voltage, a difference between a plurality of anti-resonant frequencies of the plurality of shunt acoustic resonators is smaller than a difference between a plurality of resonant frequencies of the plurality of shunt acoustic resonators when the DC voltage is generated.