Electroacoustic filter including split resonator with detuning

A wireless communication apparatus comprising:

• a frequency band filter circuit having a resonator, the resonator comprising:
• a piezoelectric material;
• a shared input busbar;
• a shared output busbar;
• a first resonator section including:
• a first input comb shaped electrode structure with a first plurality of electrode fingers coupled to the shared input busbar and extending from the shared input busbar toward the shared output busbar;
• and
• a first output comb shaped electrode structure with a first plurality of electrode fingers coupled to the shared output busbar and extending from the shared output busbar toward the shared input busbar, wherein the first input comb shaped electrode structure and the first output comb shaped electrode structure are arranged with electrode fingers positioned in an interdigitated manner and having a first periodicity;
• and
• a second resonator section positioned separately from the first resonator section along the shared input busbar and the shared output busbar, the second resonator section comprising:
• a second input comb shaped electrode structure with a second plurality of electrode fingers coupled to the shared input busbar and extending from the shared input busbar toward the shared output busbar;
• and
• a second output comb shaped electrode structure with a second plurality of electrode fingers coupled to the shared output busbar and extending from the shared output busbar toward the shared input busbar, the second input comb shaped electrode structure and the second output comb shaped electrode structure arranged with electrode fingers positioned in an interdigitated manner having a second periodicity different from the first periodicity, wherein the second resonator section is positioned further than the first resonator section from a current input and a current output of the resonator, wherein the first periodicity is associated with a first resonance, and wherein the second periodicity is associated with a second resonance offset from the first resonance by a detuning amount, wherein the detuning amount is a frequency values less than 20 megahertz (MHz), such that the first resonance is within 20 MHz of the second resonance.

A wireless communication apparatus comprising:

• a frequency band filter circuit having a split resonator, the split resonator comprising:
• a resonator including a first section of a shared input busbar, a first section of a shared output busbar, and an electrode structure between the first section of the shared input busbar and the first section of the shared output busbar, the electrode structure configured for a resonance;
• a detuned resonator including a second section of the shared input busbar, a second section of the shared output busbar, and a detuned electrode structure between the second section of the shared input busbar and the second section of the shared output busbar, the detuned electrode structure configured for a detuned resonance different from the resonance;
• and
• a pad electrically coupled to the split resonator, wherein the detuned resonance is selected to compensate for an inductance from the pad.