Acoustic filtering circuitry including capacitor

A method for manufacturing acoustic filtering circuitry comprising:

• providing a piezoelectric layer;
• providing a first metal layer on a surface of the piezoelectric layer;
• patterning the first metal layer to provide a plurality of transducers and a first plate;
• providing a dielectric layer over the surface of the piezoelectric layer and the first metal layer;
• providing a second metal layer on a surface of the dielectric layer opposite the piezoelectric layer;
• and
• patterning the second metal layer to provide a waveguide over each of the transducers and a second plate over the first plate such that the second plate and the first plate are separated by at least a portion of the dielectric layer to form a capacitor.

Acoustic filtering circuitry comprising:

• an input node, an output node, and a ground node;
• a piezoelectric layer;
• a dielectric layer over a surface of the piezoelectric layer;
• a plurality of acoustic resonators each comprising a transducer on the surface of the piezoelectric layer such that the transducer is between a portion of the piezoelectric layer and the dielectric layer;
• a capacitor comprising:
• a first plate on the surface of the piezoelectric layer such that the first plate is between a portion of the piezoelectric layer and the dielectric layer;
• and
• a second plate over the first plate such that the second plate and the first plate are separated by at least a portion of the dielectric layer;
• and
• a plurality of metal traces over a surface of the dielectric layer, wherein the plurality of metal traces electrically couple the plurality of acoustic resonators and the capacitor between the input node, the output node, and the ground node such that:
• a first set of the plurality of acoustic resonators is coupled in series between the input node and the output node to form a series signal path;
• a second set of the plurality of acoustic resonators is coupled in parallel between the series signal path and the ground node to form a plurality of shunt signal paths;
• and
• the capacitor is directly coupled between the series signal path and the ground node.