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.

Embodiments of resonator circuits and modulating resonators and are described generally herein. One or more acoustic wave resonators may be coupled in series or parallel to generate tunable filters. One or more acoustic wave resonances may be modulated by one or more capacitors or tunable capacitors. One or more acoustic wave modules may also be switchable in a filter. Other embodiments may be described and claimed.

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.

An acoustic wave device includes: a piezoelectric thin film resonator that is connected between a first node and a second node; and a resonant circuit that is connected in parallel with the piezoelectric thin film resonator between the first node and the second node, and has a resonant frequency f0 that meets a condition of 2×fa×0.92≦f0 where fa represents an antiresonant frequency of the piezoelectric thin film resonator.

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.

An acoustic resonator filter includes at least one series acoustic resonator electrically connected between a first port and a second port in series, through which a radio frequency (RF) signal passes; at least one second shunt acoustic resonator electrically shunt-connected between the at least one series acoustic resonator and a ground; and at least one first shunt acoustic resonator electrically shunt-connected between the at least one series acoustic resonator and a ground and having a resonance frequency higher than a resonance frequency of the at least one second shunt acoustic resonator. At least one shunt acoustic resonator, among the at least one first shunt acoustic resonator and the at least one second shunt acoustic resonator has a temperature coefficient of frequency (TCF) corresponding to resonance frequency sensitivity more insensitive than resonance frequency sensitivity according to a change in temperature of the at least one series acoustic resonator filter.

Acoustic wave devices are disclosed. An acoustic wave device can include a first filter and a second filter coupled to a common node. The second filter includes acoustic wave resonators of a first type (e.g., bulk acoustic wave resonators) and a series acoustic wave resonator of the second type (e.g., a surface acoustic wave resonator) that is coupled between the acoustic wave resonators of the first type and the common node. The acoustic wave device can further include a loop circuit coupled to the first filter, in which the loop circuit is configured to generate an anti-phase signal to a target signal at a particular frequency. In certain embodiments, the first filter is a receive filter and the second filter is a transmit filter.

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.