Acoustic wave filter with second harmonic emission suppression

An acoustic wave filter with second harmonic emission suppression, the acoustic wave filter comprising:

• a first pair of bulk acoustic wave resonators in anti-series with each other, the first pair of bulk acoustic wave resonators including a first bulk acoustic wave resonator and a second bulk acoustic wave resonator;
• a second pair of bulk acoustic wave resonators in anti-series with each other, the second pair of bulk acoustic wave resonators being in parallel with the first pair of bulk acoustic wave resonators, and the second pair of bulk acoustic wave resonators having reverse electrode polarization relative to the first pair of bulk acoustic wave resonators;
• a plurality of additional acoustic wave resonators that includes a pair of series bulk acoustic wave resonators in anti-series with each other in a filter stage;
• and
• a capacitor connected to a common electrode of the first bulk acoustic wave resonator and the second bulk acoustic wave resonator, the capacitor configured to compensate for a mismatch in parasitic capacitance between the first pair of bulk acoustic wave resonators and the second pair of bulk acoustic wave resonators, the acoustic wave filter configured to filter a radio frequency signal.

An acoustic wave filter with second harmonic emission suppression, the acoustic wave filter comprising:

• a first pair of bulk acoustic wave resonators in anti-series with each other, the first pair of bulk acoustic wave resonators including a first bulk acoustic wave resonator and a second bulk acoustic wave resonator;
• a second pair of bulk acoustic wave resonators in anti-series with each other, the second pair of bulk acoustic wave resonators being in parallel with the first pair of bulk acoustic wave resonators, and the second pair of bulk acoustic wave resonators having reverse electrode polarization relative to the first pair of bulk acoustic wave resonators;
• and
• a capacitor connected to a common electrode of the first bulk acoustic wave resonator and the second bulk acoustic wave resonator, the capacitor configured to compensate for a mismatch in parasitic capacitance between the first pair of bulk acoustic wave resonators and the second pair of bulk acoustic wave resonators, the acoustic wave filter configured to filter a radio frequency signal, and the capacitor includes at least one of an interdigital transducer electrode capacitor, a resonator capacitor, a near metal capacitor, or a metal-insulator-metal capacitor.

An acoustic wave filter with second harmonic emission suppression, the acoustic wave filter comprising:

• a first pair of bulk acoustic wave resonators in anti-series with each other, the first pair of bulk acoustic wave resonators including a first bulk acoustic wave resonator and a second bulk acoustic wave resonator;
• a second pair of bulk acoustic wave resonators in anti-series with each other, the second pair of bulk acoustic wave resonators being in parallel with the first pair of bulk acoustic wave resonators, and the second pair of bulk acoustic wave resonators having reverse electrode polarization relative to the first pair of bulk acoustic wave resonators;
• a pair of shunt bulk acoustic wave resonators in anti-series with each other and a second capacitor connected to a common electrode of the pair of shunt bulk acoustic wave resonators;
• and
• a capacitor connected to a common electrode of the first bulk acoustic wave resonator and the second bulk acoustic wave resonator, the capacitor configured to compensate for a mismatch in parasitic capacitance between the first pair of bulk acoustic wave resonators and the second pair of bulk acoustic wave resonators, the acoustic wave filter configured to filter a radio frequency signal.

A radio frequency module comprising:

• an acoustic wave filter including a first pair of bulk acoustic wave resonators in anti-series with each other, a second pair of bulk acoustic wave resonators in anti-series with each other and having reverse electrode polarization relative to the first pair of bulk acoustic wave resonators, and a capacitor connected to a common electrode of a first bulk acoustic wave resonator and a second bulk acoustic wave resonator of the first pair of bulk acoustic wave resonators;
• radio frequency circuitry coupled to the acoustic wave filter;
• and
• a package structure enclosing the acoustic wave filter and the radio frequency circuitry.