A ladder filter comprises a plurality of series arm bulk acoustic wave resonators electrically connected in series between an input port and an output port of the ladder filter and a plurality of shunt bulk acoustic wave resonators electrically connected in parallel between adjacent ones of the plurality of series arm bulk acoustic wave resonators and ground, at least one of the plurality of shunt bulk acoustic wave resonators including raised frame regions having a first width, at least one of the plurality of series arm bulk acoustic wave resonators having one of raised frame regions having a second width less than the first width or lacking raised frame regions.

A thin-film package includes: a substrate; a wiring layer disposed on the substrate; a microelectromechanical systems (MEMS) element disposed on a surface of the substrate; a partition wall disposed on the substrate to surround the MEMS element, and formed of a polymer material; a cap forming a cavity with the substrate and the partition wall; and an external connection electrode connected to the wiring layer. The external connection electrode includes at least one inclined portion disposed on at least one inclined surface formed on any one or any combination of any two or more of the substrate, the partition wall, and the cap.

A structure of an acoustic transducer array probe for transmission of acoustic waves from a front radiation surface into an acoustic load material, where said acoustic waves can have frequencies in a high frequency (HF) band and further lower frequency (LF1, . . . , LFn, . . . , LFN) bands with N1, arranged in order of decreasing center frequency. The acoustic waves are transmitted from separate high and lower frequency arrays stacked together with matching layers in a thickness dimension into a layered structure, with at least a common radiation surface for said high and lower frequency bands. At least for said common radiation surface at least one lower frequency LFn electro-acoustic structure (n=1, . . . , N) comprises a piezoelectric array with an acoustic isolation section to its front face. The acoustic isolation section includes to the front a section composed of a sequence of L3 matching layers with interchanging low and high characteristic impedances, where the front layer of said section is one of i) a lower characteristic impedance layer, and ii) a higher characteristic impedance layer, and where at least one lower characteristic impedance layer is made of a homogeneous material.

A film bulk acoustic wave resonator (FBAR) comprises a recessed frame region including an undulating perimeter.

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.

A multiplexer includes a first filter connected to a common terminal and a first input/output terminal, a second filter connected to the common terminal and a second input/output terminal, a first cancel circuit including a first terminal, a second terminal acoustically connected to the first terminal, and a third terminal acoustically connected to the first terminal, and a second cancel circuit including a fourth terminal, and a fifth terminal acoustically connected to the fourth terminal. The first terminal is connected to the first input/output terminal. The second terminal is connected to the second input/output terminal. The fourth terminal is connected to the third terminal. The fifth terminal is connected to the second input/output terminal. The first and second cancel circuits generate signals that cancel out unnecessary signals in a prescribed frequency band propagating between the first and second input/output terminals.

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 thin-film package includes: a substrate; a wiring layer disposed on the substrate; a microelectromechanical systems (MEMS) element disposed on a surface of the substrate; a partition wall disposed on the substrate to surround the MEMS element, and formed of a polymer material; a cap forming a cavity with the substrate and the partition wall; and an external connection electrode connected to the wiring layer. The external connection electrode includes at least one inclined portion disposed on at least one inclined surface formed on any one or any combination of any two or more of the substrate, the partition wall, and the cap.

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.

The acoustic wave filter (10A) includes a parallel-arm resonant circuit (12p). The parallel-arm resonant circuit (12p) includes a parallel-arm resonator (p1) and a frequency variable circuit (72p) that are connected in parallel. The frequency variable circuit (72p) includes a parallel-arm resonator (p2) that has a resonant frequency higher than that of the parallel-arm resonator (p1) and a switch (SW1) element. A frequency difference between a resonant frequency on a higher frequency side of the parallel-arm resonant circuit (12p) in a case where the switch (SW1) is OFF and a resonant frequency on a higher frequency side of the parallel-arm resonant circuit (12p) in a case where the switch (SW1) is ON is equal to or more than a frequency difference between a low frequency end frequency of the second attenuation band and a low frequency end frequency of the first attenuation band.