Abstract: An acoustic wave device includes an acoustic wave filter configured to filter a radio frequency signal and a loop circuit coupled to the acoustic wave filter. The loop circuit is configured to generate an anti-phase signal to a target signal at a particular frequency. The loop circuit includes a Lamb wave resonator having a piezoelectric layer and an interdigital transducer electrode disposed on the piezoelectric layer. The piezoelectric layer includes free edges. An edge of the piezoelectric layer is configured to one of suppress or scatter reflections of acoustic waves generated by the interdigital transducer electrode from the edge of the piezoelectric layer.

Abstract: A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.

Abstract: A surface acoustic wave device has a trench formed adjacent to at least one interdigital transducer electrode into the piezoelectric substrate. The trench can be adapted to enhance confinement of acoustic wave energy provided by the interdigital transducer electrode.

Abstract: A laterally excited bulk acoustic wave device is disclosed. The laterally excited bulk acoustic wave device can include a first solid acoustic mirror, a second solid acoustic mirror, a piezoelectric layer that is positioned between the first solid acoustic mirror and the second solid acoustic mirror, an interdigital transducer electrode on the piezoelectric layer, and a support substrate arranged to dissipate heat associated with the bulk acoustic wave. The interdigital transducer electrode is arranged to laterally excite a bulk acoustic wave. The first solid acoustic mirror and the second solid acoustic mirror are arranged to confine acoustic energy of the bulk acoustic wave. The first solid acoustic mirror is positioned on the support substrate.

Abstract: Aspects of this disclosure relate to a surface acoustic wave filter with an acoustic velocity adjustment structure. The surface acoustic wave filter can include a first interdigital transducer electrode disposed on a piezoelectric layer, an acoustic reflector disposed on the piezoelectric layer, and a second interdigital transducer electrode disposed on the piezoelectric layer. The second interdigital transducer electrode is longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector. The acoustic velocity adjustment structure can be positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode.

Abstract: Aspects of this disclosure relate to a multiplexer, such as a duplexer, a quadplexer, a hexaplexer, or the like. The multiplexer includes acoustic wave filters coupled to a common node. A first acoustic wave filter of the acoustic wave filters includes acoustic wave resonators of a first type and a series acoustic wave resonator of a second type coupled between the acoustic wave resonators of the first type and the common node.

Abstract: Embodiments of this disclosure relate to reducing coupling between acoustic wave resonators. An isolation region of a substrate can be located between acoustic wave resonators. The isolation region can reduce capacitive coupling through the substrate between the acoustic wave resonators. In certain embodiments, the isolation region can be located between acoustic wave resonators of different filters to thereby increase isolation between the filters.

Abstract: Aspects of this disclosure relate to a surface acoustic wave filter with an integrated temperature sensor. The integrated temperature sensor can be a resistive thermal device configured as a reflective grating for a surface acoustic wave resonator, for example. A radio frequency system can provide over temperature protection by reducing a power level of a radio frequency signal provided to the surface acoustic wave filter responsive to an indication of temperature provided by the integrated temperature sensor satisfying a threshold.

Abstract: Aspects of this disclosure relate to a multiplexer, such as a duplexer, a quadplexer, a hexaplexer, or the like. The multiplexer includes acoustic wave filters coupled to a common node. A first acoustic wave filter of the acoustic wave filters includes acoustic wave resonators of a first type and a series acoustic wave resonator of a second type coupled between the acoustic wave resonators of the first type and the common node.

Abstract: Aspects of this disclosure relate to an acoustic wave filter with an acoustic wave resonator arranged to concentrate a transverse spurious mode at a frequency. Such an acoustic wave resonator can have a narrow aperture to concentrate the transverse spurious mode. The transverse spurious mode can increase steepness of a skirt of the acoustic wave filter. Related methods, acoustic wave devices, multiplexers, radio frequency front ends, radio frequency modules, and wireless communication devices are disclosed.

Abstract: Embodiments of this disclosure relate to reducing coupling between acoustic wave resonators. An isolation region of a substrate can be located between acoustic wave resonators. The isolation region can reduce capacitive coupling through the substrate between the acoustic wave resonators. In certain embodiments, the isolation region can be located between acoustic wave resonators of different filters to thereby increase isolation between the filters.

Abstract: Aspects of this disclosure relate to a surface acoustic wave device that includes a first reflector over a piezoelectric layer, a second reflector over the piezoelectric layer, and an interdigital transducer electrode structure over the piezoelectric layer and positioned between the first reflector and the second reflector. The surface acoustic wave device includes a velocity adjustment layer arranged to adjust acoustic velocity in a region of the surface acoustic wave device. The velocity adjustment layer can be a high speed layer or a low speed layer.

Abstract: Aspects of this disclosure relate to a surface acoustic wave filter with an acoustic velocity adjustment structure. The surface acoustic wave filter can include a first interdigital transducer electrode disposed on a piezoelectric layer, an acoustic reflector disposed on the piezoelectric layer, and a second interdigital transducer electrode disposed on the piezoelectric layer. The second interdigital transducer electrode is longitudinally coupled to the first interdigital transducer electrode and positioned between the first interdigital transducer electrode and the acoustic reflector. The acoustic velocity adjustment structure can be positioned over at least a gap between the first interdigital transducer electrode and the second interdigital transducer electrode.

Abstract: Filters and acoustic resonators for radio-frequency circuits and devices. In some embodiments, a radio-frequency circuit can include a plurality of nodes and a common node. The radio-frequency circuit can further include a signal path implemented between each of the plurality of nodes and the common node. Each corresponding signal path can include a filter having a first Q-factor value and a respective resonator having a second Q-factor value higher than the first Q-factor value.

Abstract: Aspects of this disclosure relate to a surface acoustic wave device with a vertical stack over a piezoelectric layer. The vertical stack can include a first acoustic reflector disposed on the piezoelectric layer, a second acoustic reflector disposed on the piezoelectric layer, and an interdigital transducer electrode disposed on the piezoelectric layer and positioned between the first acoustic reflector and the second acoustic reflector. The interdigital transducer electrode has a first side that is closer to the first acoustic reflector and a second side that is closer to the second acoustic reflector. A vertical arrangement of the vertical stack can be configured such that an acoustic wave propagation velocity of a first region between the first side and a first reflector is faster than an acoustic wave propagation velocity of a second region between the first side and the second side.

Abstract: Aspects of this disclosure relate to an acoustic wave filter with an acoustic wave resonator arranged to concentrate a transverse spurious mode at a frequency. Such an acoustic wave resonator can have a narrow aperture to concentrate the transverse spurious mode. The transverse spurious mode can increase steepness of a skirt of the acoustic wave filter. Related methods, acoustic wave devices, multiplexers, radio frequency front ends, radio frequency modules, and wireless communication devices are disclosed.

Abstract: Circuits with filters and acoustic resonators. In some embodiments, a radio-frequency circuit can include a plurality of nodes and a common node. The radio-frequency circuit can further include a signal path implemented between each of the plurality of nodes and the common node. Each corresponding signal path can include a filter having a first Q-factor value and a respective resonator having a second Q-factor value higher than the first Q-factor value.

Abstract: An integrated bulk acoustic wave resonator-capacitor comprises a membrane including a piezoelectric film, an upper electrode disposed on a top surface of the piezoelectric film, and a lower electrode disposed on a lower surface of the piezoelectric film, a resonator region of the membrane defining a main active domain in which a main acoustic wave is generated during operation, and a capacitor region of the membrane surrounding the resonator region, the capacitor region including a layer of conductive material disposed on the upper electrode, an inner capacitor raised frame defined on an inner peripheral region of the layer of conductive material, and an outer capacitor raised frame defined on an outer peripheral region of the layer of conductive material.

Abstract: Tunable cavity waveguides are disclosed. In certain embodiments, a tunable cavity waveguide includes a controllable tunnel structure including a signal feed configured to receive a millimeter wave signal, and a plurality of controllable tunnel walls providing a waveguide for the millimeter wave signal. The unable cavity waveguide further includes a control circuit configured to control the waveguide by individually setting each of the plurality of controllable tunnel walls in a blocking state in which the millimeter wave signal is blocked or a transparent state in which the millimeter wave signal is passed.

Abstract: Crossbar switches for coarse phase shifting are disclosed. In certain embodiments, a mobile device includes an antenna array including a plurality of antennas. The mobile device further includes a front end system coupled to the antenna array and including a plurality of signal conditioning circuits each including a phase shifter. The plurality of signal conditioning circuits each provide phase shifting to a respective one of a plurality of radio frequency signals based on a fine control signal. The front end system further includes a crossbar switch coupled to the plurality of signal conditioning circuits and configured to provide phase shifting to the plurality of radio frequency signals based on a coarse control signal.