An acoustic waveguide having high-Q resonator characteristics is disclosed and a fabrication method is described. Various waveguide-based test-vehicles, implemented in single crystal silicon and transduced by thin aluminum nitride films, are demonstrated. Silicon resonators with type-I and type-II dispersion characteristics are presented to experimentally justify the analytical mode synthesis technique for realization of high quality-factor silicon Lamb wave resonators. An analytical design procedure is also presented for geometrical engineering of the waveguides to realize high-Q resonators without the need for geometrical suspension through narrow tethers or rigid anchors. The effectiveness of the dispersion engineering methodology is verified through development of experimental test-vehicles in 20 μm-thick single-crystal silicon (SCS) waveguides with 500 nm aluminum nitride transducers.

An RF circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.

A composite acoustic wave filter device includes first and second acoustic wave filters. One end of the first acoustic wave filter with a pass band in a relatively low frequency range and one end of the second acoustic wave filter with a pass band in a relatively high frequency range are connected in common. A first end portion of a first parallel capacitance element and a third end portion of a second parallel capacitance element are connected to a signal line of the second acoustic wave filter. A ground-side end portion of the first parallel capacitance element is connected in common to a ground-side end portion of the first acoustic wave filter. A fourth end portion of the second parallel capacitance element is connected to a ground potential.

An RF triplexer circuit device using modified lattice, lattice, and ladder circuit topologies. The devices can include four resonator devices and four shunt resonator devices. In the ladder topology, the resonator devices are connected in series from an input port to an output port while shunt resonator devices are coupled the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a pair of resonator devices that are coupled to differential input and output ports. A pair of shunt resonators is cross-coupled between each pair of a top serial configuration resonator and a bottom serial configuration resonator. The modified lattice topology adds baluns or inductor devices between top and bottom nodes of the top and bottom serial configurations of the lattice configuration. These topologies may be applied using single crystal or polycrystalline bulk acoustic wave (BAW) resonators.

An ultrasonic device may include an electromechanical ultrasonic system defined by a predetermined resonant frequency and include an ultrasonic transducer coupled to an ultrasonic blade. A method of delivering energy to the device may include applying energy to the blade at a first power level via the transducer coupled to the blade, measuring a complex impedance of the transducer, receiving a complex impedance feedback data point, comparing the complex impedance feedback data point to a reference complex impedance characteristic pattern, and determining that the blade is contacting a vessel based on the comparison. The method may also include disabling the power applied to the transducer and switching to a lower power level. The method may further include generating a warning that the blade is contacting a vessel, such as a light or a sound. An ultrasonic surgical instrument may effect the method.

An acoustic filter device for telecommunication devices includes a first acoustic band pass filter having a corresponding first passband and a second acoustic band pass filter having a corresponding second passband. The second acoustic band pass filter is connected in parallel with the first acoustic band pass filter to provide a combined passband including the first and second passbands.

An elastic wave element having a piezoelectric substrate equipped with a first main surface, and an excitation electrode arranged on the first main surface and having multiple electrode fingers, wherein, in a cross-sectional view in the direction orthogonal to the first main surface, the width of the electrode fingers at a first height at a distance from the first main surface is greater than the width at a second height located closest to the first main surface.

Certain aspects of the present disclosure provide a filter circuit and techniques for filtering using the filter circuit. The filter circuit generally includes a first filter stage having a first acoustic wave resonator coupled in a series path between a first port of the filter circuit and a second port of the filter circuit, a first inductor-capacitor (LC) tank circuit, a first capacitor coupled between a first terminal of the first acoustic wave resonator and the first LC tank circuit, the first LC tank circuit being coupled between the first capacitor and a reference potential node, and a second capacitor coupled between a second terminal of the first acoustic wave resonator and the first LC tank circuit. In some aspects, the filter circuit includes one or more other filter stages coupled to the first filter stage.

A film bulk acoustic wave resonator (FBAR) includes a piezoelectric film disposed in a central region defining a main active domain in which a main acoustic wave is generated during operation, and in recessed frame regions disposed laterally on opposite sides of the central region. The piezoelectric film disposed in the recessed frame regions includes a greater concentration of defects than a concentration of defects in the piezoelectric film disposed in the central region.

A multi-stage matching network filter circuit device. The device comprises bulk acoustic wave (BAW) resonator device having an input node, an output node, and a ground node. A first matching network circuit is coupled to the input node. A second matching network circuit is coupled to the output node. A ground connection network circuit coupled to the ground node. The first or second matching network circuit can include an inductive ladder network including a plurality of series inductors in a series configuration and a plurality of grounded inductors wherein each of the plurality of grounded inductors is coupled to the connection between each connected pair of series inductors. The inductive ladder network can include one or more LC tanks, wherein each of the one or more LC tanks is coupled between a connection between a series inductor and a subsequent series inductor, which is also coupled to a grounded inductor.