Abstract: Aspects of this disclosure relate to acoustic wave filters with bulk acoustic wave resonators. An acoustic wave filter can include a first bulk acoustic wave resonator configured to excite an overtone mode as a main mode and a second bulk acoustic wave resonator having a fundamental mode as a main mode.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device with a multi-gradient raised frame. The bulk acoustic wave device includes a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a multi-gradient raised frame structure configured to cause lateral energy leakage from a main acoustically active region of the bulk acoustic wave device to be reduced. The multi-gradient raised frame structure is tapered on opposing sides.

Abstract: A filter with bulk acoustic wave devices is disclosed. The filter includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The first bulk acoustic wave resonator includes a first raised frame structure. The first raised frame structure is a multi-layer raised frame structure. The second bulk acoustic wave resonator includes a second raised frame structure. The first raised frame structure has at least one more raised frame layer than the second raised frame structure.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device with a multi-gradient raised frame. The bulk acoustic wave device includes a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a multi-gradient raised frame structure. The multi-gradient raised frame structure includes a first raised frame layer and a second raised frame layer. The second raised frame layer extends beyond the first raised frame layer. The second raised frame layer is tapered on opposing sides.

Abstract: Aspects of this disclosure relate to acoustic wave filters with bulk acoustic wave resonators configured to excite an overtone mode as a main mode. A bulk acoustic wave resonator of the filter can include a plurality of stacked piezoelectric layers positioned between a pair of electrodes.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes a shunt a bulk acoustic wave resonator having a plurality of resonant frequencies that impact a passband of the acoustic wave filter. Related bulk acoustic wave resonators, radio frequency modules, wireless communication devices, and methods of filtering radio frequency signals are disclosed.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes a series a bulk acoustic wave resonator having a plurality of anti-resonant frequencies that impact a passband of the acoustic wave filter. Related bulk acoustic wave resonators, radio frequency modules, wireless communication devices, and methods of filtering radio frequency signals are disclosed.

Abstract: Aspects of this disclosure relate to an acoustic wave filter that includes a shunt a bulk acoustic wave resonator having a plurality of resonant frequencies that impact a passband of the acoustic wave filter. Related bulk acoustic wave resonators, radio frequency modules, wireless communication devices, and methods of filtering radio frequency signals are disclosed.

Abstract: An acoustic wave filter with different bulk acoustic wave devices is disclosed. The filter includes a first bulk acoustic wave resonator and a second bulk acoustic wave resonator. The first bulk acoustic wave resonator includes a first raised frame structure. The first raised frame structure is a multi-layer raised frame structure. The second bulk acoustic wave resonator includes a second raised frame structure. The first raised frame structure has at least one more raised frame layer than the second raised frame structure.

Abstract: A bulk acoustic wave device includes a first electrode, a second electrode, and a piezoelectric layer positioned between the first electrode and the second electrode. A first raised frame structure outside of a middle area of an active domain of the bulk acoustic wave device, the raised frame structure including a first raised frame layer positioned between the first electrode and the second electrode and having a lower acoustic impedance than the first electrode. A mass-loading layer is disposed between the first raised frame layer and the piezoelectric layer. A thickness of the mass-loading layer is less than 50% of the thickness of the first raised frame layer. The first raised frame layer extends further into the active domain of the bulk acoustic wave device than the mass-loading layer.

Abstract: A bulk acoustic wave device includes a first electrode, a second electrode, and a piezoelectric layer positioned between the first electrode and the second electrode. A first raised frame layer outside of a middle area of an active domain of the bulk acoustic wave device, positioned between the first electrode and the second electrode and having a lower acoustic impedance than the first electrode. A second layer is disposed between the first raised frame layer and the piezoelectric layer, the second layer thinner than the first raised frame layer and formed of a different material than the first raised frame layer, and the first raised frame layer.

Abstract: Methods related to gradient raised frames in film bulk acoustic resonators. According to certain aspects, a method for fabricating a film bulk acoustic resonator device can include: forming a first metal layer over a substrate; forming a piezoelectric layer; forming a second metal layer, the piezoelectric layer positioned between the first and second metal layers; and forming a gradient raised frame implemented relative to one of the first and second metal layers and configured to improve reflection of lateral mode waves and to reduce conversion of main mode waves into lateral mode waves.

Abstract: An acoustic wave device with a bent section is disclosed. The acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode on the piezoelectric layer. The bent section is arranged to create a curvature in a waveguide of the acoustic wave device to suppress a transverse spurious mode of the acoustic wave device.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device with a multi-layer raised frame. The bulk acoustic wave device includes a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a multi-layer raised frame structure configured to cause lateral energy leakage from a main acoustically active region of the bulk acoustic wave device to be reduced. The multi-layer raised frame structure includes a first raised frame layer embedded in the piezoelectric layer and a second raised frame layer. The first raised frame layer has a lower acoustic impedance than the piezoelectric layer.

Abstract: Disclosed herein is a bulk acoustic wave filter comprising a number of acoustic wave resonators, each acoustic wave resonator being encompassed by a polygon including vertices of a mesh optimized to provide a reduced filter size of the bulk acoustic wave filter integrated on a die.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device that includes a multi-layer raised frame structure. The multi-layer raised frame structure includes a first raised frame layer positioned between a first electrode and a second electrode of the bulk acoustic wave device. The first raised frame layer has a lower acoustic impedance than the first electrode. The first raised frame layer and the second raised frame layer overlap in an active region of the bulk acoustic wave device. Related filters, multiplexers, packaged modules, wireless communication devices, and methods are disclosed.

Abstract: Aspects of this disclosure relate bulk acoustic wave resonators with a patterned mass loading layer at least contributing to a difference in mass loading between a main acoustically active region of the bulk acoustic wave resonator and a recessed frame region of the bulk acoustic wave resonator. Related methods of manufacturing can involve forming the patterned mass loading layer in the main acoustically active region and the recessed frame region in a common processing step such that the patterned mass loading layer has a higher density in the main acoustically active region than in the recessed frame region.

Abstract: Aspects of this disclosure relate to bulk acoustic wave resonators with patterned mass loading layers. Two different bulk acoustic wave resonators of an acoustic wave filter and/or an acoustic wave die have respective patterned mass loading layers with different densities. The patterned mass loading layers contribute to the two different bulk acoustic wave resonators having different respective resonant frequencies. Related bulk acoustic wave devices, filters, acoustic wave dies, radio frequency modules, wireless communication devices, and methods are disclosed.

Abstract: Aspects of this disclosure relate to a bulk acoustic wave device with a floating raised frame structure. The bulk acoustic wave device includes a first electrode, a second electrode, a piezoelectric layer positioned between the first electrode and the second electrode, and a floating raised frame structure positioned on a same side of the piezoelectric layer as the first electrode and spaced apart from the first electrode. The floating raised frame structure is at a floating potential. The bulk acoustic wave device can suppress a raised frame mode. Related methods, filters, multiplexers, radio frequency front ends, radio frequency modules, and wireless communication devices are disclosed.

Abstract: Gradient raised frames in film bulk acoustic resonators. In some embodiments, a film bulk acoustic resonator device can include a substrate, first and second metal layers implemented over the substrate, a piezoelectric layer between the first and second metal layers, and a gradient raised frame implemented relative to one of the first and second metal layers and configured to improve reflection of lateral mode waves and to reduce conversion of main mode waves into lateral mode waves.