Filters and methods of making filters are disclosed. A filter device includes a substrate, a piezoelectric plate, and an acoustic Bragg reflector between a surface of the substrate and a back surface of the piezoelectric plate. A first portion of the piezoelectric plate has a first thickness, and a second portion of the piezoelectric plate has a second thickness less than the first thickness. A conductor pattern on front surfaces of the first and second portions of the piezoelectric plate includes a first interdigital transducer (IDT) with interleaved fingers on the first portion, and a second IDT with interleaved fingers on the second portion.

A resonance circuit complex electronic component includes a first circuit element and a second circuit element defining a resonance circuit, an external connection terminal connected to outside, and a plurality of routing conductors connecting an external terminal of the first circuit element and an external terminal of the second circuit element to the external connection terminal, respectively. At least one of the plurality of routing conductors includes an inductor conductor extending in a direction not in parallel with a mounting surface.

A reactance filter includes a series branch that connects a signal input to a signal output. At least one parallel branch branches off from the series branch with respect to ground. A parallel resonator is arranged in each parallel branch. Two or more series resonators are connected in series in the series branch. A capacitor is connected in parallel with one of the series resonators in the series branch.

An apparatus is disclosed for implementing a microacoustic filter with an acoustically-decoupled electrode structure. In an example aspect, the apparatus includes the microacoustic filter with a piezoelectric layer, a substrate, and an electrode structure. The piezoelectric layer has a crystalline structure operative to laterally excite a plate mode. The electrode structure is positioned between the piezoelectric layer and the substrate and has a has a first surface that faces the piezoelectric layer. The microacoustic filter also includes at least one spacer extending from the substrate past a plane defined by the first surface of the electrode structure and towards the piezoelectric layer to form a cavity between the electrode structure and the piezoelectric layer.

An RF diplexer circuit device using modified lattice, lattice, and ladder circuit topologies. The diplexer can include a pair of filter circuits, each with a plurality of series resonator devices and shunt resonator devices. In the ladder topology, the series resonator devices are connected in series while shunt resonator devices are coupled in parallel to the nodes between the resonator devices. In the lattice topology, a top and a bottom serial configurations each includes a plurality of series resonator devices, and 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. A multiplexing device or inductor device can be configured to select between the signals coming through the first and second filter circuits.

A resonator, a resonator assembly, a filter, an electronic device, and a method for manufacturing the resonator. The resonator comprises: a substrate, comprising a first surface and a second surface opposite to each other; a first electrode, located on the first surface, where the first electrode comprises a first protruding portion protruding away from the first surface and a first flat portion attached on the first surface, and a cavity is formed between the first protruding portion and the first surface; a piezoelectric layer, located at a side of the first electrode away from the substrate, where the piezoelectric layer extends in parallel with the first surface; and a second electrode, located at a side of the piezoelectric layer away from the first electrode.

An acoustic wave device includes a first acoustic wave resonator including a first piezoelectric film, and at least one second acoustic wave resonator electrically connected to the first acoustic wave resonator. The first acoustic wave resonator includes a first comb-shaped electrode on a first piezoelectric layer and including first electrode fingers connected to an input potential, a second comb-shaped electrode on the first piezoelectric layer and including second electrode fingers interdigitated with the first electrode fingers, and connected to an output potential, and a third electrode connected to a potential different from those connected to the first and second comb-shaped electrodes, and including third electrode fingers, and a connection electrode connecting adjacent third electrode fingers. The second acoustic wave resonator includes fourth and fifth electrode fingers interdigitated with each other. The second acoustic wave resonator is a series arm resonator or a parallel arm resonator.

A filter device is provided that includes a piezoelectric layer having a first portion having a first thickness and a second portion having a second thickness less than the first thickness; an acoustic multilayer reflector attached to the piezoelectric layer; and a conductor pattern on the first portion and the second portion of the piezoelectric layer. The conductor pattern includes a first IDT with interleaved fingers on the first portion, and a second IDT with interleaved fingers on the second portion. At least a portion of interleaved fingers of the second IDT has a width that is greater than or equal to 0.2 times a pitch of the second IDT and less than or equal to 0.3 times the pitch of the second IDT.

An acoustic wave device includes first and second acoustic wave resonators. Each of the first and second acoustic wave resonators includes a piezoelectric film including a piezoelectric layer, first and second comb-shaped electrodes, and a third electrode. The first comb-shaped electrode includes a first busbar and first electrode fingers. The second comb-shaped electrode includes a second busbar and second electrode fingers. The third electrode includes third electrode fingers and a connection electrode. The third electrode fingers are arranged side by side with the first and second electrode fingers. The connection electrode connects adjacent third electrode fingers. An arrangement order of the first, second, and third electrode fingers is the first electrode finger, the third electrode finger, the second electrode finger, and the third electrode finger repeated as one period. Each of the first and second acoustic wave resonators is a divided resonator including an acoustic wave resonator divided in series.

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.