Abstract: The present disclosure relates to a Bulk Acoustic Wave (BAW) resonator, which includes a bottom electrode, a top electrode structure, and a multilayer transduction structure sandwiched therebetween. Herein, the multilayer transduction structure is composed of multiple transduction layers, at least one of which is formed of a ferroelectric material with a box-shape polarization-electric field curve. Each transduction layer includes a transduction border (BO) portion positioned at a periphery of a corresponding transduction layer and a transduction central portion surrounded by the transduction BO portion. A combination of all transduction BO portions forms a transduction BO section of the multilayer transduction structure, and a combination of all transduction central portions forms a transduction central section of the multilayer transduction structure.

Abstract: Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

Abstract: Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

Abstract: Disclosed is a Bulk Acoustic Wave (BAW) filter structure with a conductive bridge forming an electrical loop with an electrode for reduced electrical losses. In exemplary aspects disclosed herein, the BAW filter structure includes a transducer with electrodes, a piezoelectric layer between the electrodes, and at least one conductive bridge offset from at least a portion of one of the electrodes by an insulating volume. The conductive bridge forms a first electrical loop between a medial end and a distal end of the electrode. Such a configuration reduces electrical resistance, heat resistance, and/or ohmic losses for improved electrical loss of the BAW filter structure.

Abstract: Acoustic filtering circuitry includes an input node, an output node, a signal transmission path, a series acoustic resonator, and a shunt acoustic resonator. The signal transmission path is between the input node and the output node. The series acoustic resonator is coupled between the input node and the output node in the signal transmission path. Further, a temperature coefficient of frequency (TCF) of a parallel resonance frequency of the series acoustic resonator is positive. The shunt acoustic resonator is coupled between the signal transmission path and ground. Further, a TCF of a series resonance frequency of the shunt acoustic resonator is negative. By providing the TCF of the series acoustic resonator and the shunt acoustic resonator in this manner, self-heating of the acoustic filtering circuitry may be significantly reduced, thereby improving the performance of the acoustic filtering circuitry.

Abstract: Acoustic filtering circuitry includes an input node, an output node, a signal transmission path, a series acoustic resonator, and a shunt acoustic resonator. The signal transmission path is between the input node and the output node. The series acoustic resonator is coupled between the input node and the output node in the signal transmission path. Further, a temperature coefficient of frequency (TCF) of a parallel resonance frequency of the series acoustic resonator is positive. The shunt acoustic resonator is coupled between the signal transmission path and ground. Further, a TCF of a series resonance frequency of the shunt acoustic resonator is negative. By providing the TCF of the series acoustic resonator and the shunt acoustic resonator in this manner, self-heating of the acoustic filtering circuitry may be significantly reduced, thereby improving the performance of the acoustic filtering circuitry.

Abstract: Bulk acoustic wave resonators having a lateral energy barrier are disclosed. In an example aspect, a resonator includes a volume of piezoelectric material, a bottom electrode, a top electrode, and a reflector. The bottom electrode is disposed below a portion of a lower surface of the volume of piezoelectric material. The top electrode is disposed above a portion of an upper surface of the volume of piezoelectric material with a portion of the top electrode overlapping a portion of the bottom electrode to define an active region of the volume of piezoelectric material configured to resonate acoustic waves having frequencies within a specified passband. The reflector is disposed on an upper surface of the volume of piezoelectric material outside of the active region with the reflector configured as a lateral energy barrier to reflect laterally propagating acoustic waves having frequencies within the specified passband.

Abstract: The invention relates to a BAW resonator with reduced heat build-up. The heat build-up is reduced by a thermal bridge, which dissipates heat from the electro-acoustically active region to a support substrate, without impairing the acoustics of the resonator.

Abstract: The invention relates to a BAW resonator with reduced heat build-up. The heat build-up is reduced by a thermal bridge, which dissipates heat from the electro-acoustically active region to a support substrate, without impairing the acoustics of the resonator.