A method of manufacturing an acoustic wave device is disclosed. The method includes attaching a support layer to a ceramic layer. The support layer has a higher thermal conductivity than the ceramic layer. The ceramic layer can be a polycrystalline spinel layer. The method also includes bonding a piezoelectric layer to a surface of the ceramic layer. The method further includes forming an interdigital transducer electrode over the piezoelectric layer.

A filter includes: one or more series resonators connected in series between an input terminal and an output terminal, the one or more series resonators including a series resonator located closest to the output terminal, the series resonator located closest to the output terminal having a resonant frequency that is 99.6% or less of or 102.2% or greater of a center frequency of a passband; one or more parallel resonators connected in parallel between the input terminal and the output terminal; and an inductor connected in parallel to the series resonator located closest to the output terminal.

Surface acoustic wave devices and related methods. In some embodiments, a surface acoustic wave device for providing resonance of a surface acoustic wave having a wavelength λ can include a quartz substrate and a piezoelectric plate formed from LiTaO.sub.3 or LiNbO.sub.3 disposed over the quartz substrate. The piezoelectric plate can have a thickness greater than 2λ. The surface acoustic wave device can further include an interdigital transducer electrode formed over the piezoelectric plate. The interdigital transducer electrode can have a mass density ρ in a range 1.50 g/cm.sup.3<ρ≤6.00 g/cm.sup.3, 6.00 g/cm.sup.3<ρ≤12.0 g/cm.sup.3, or 12.0 g/cm.sup.3<ρ≤23.0 g/cm.sup.3, and a thickness greater than 0.148λ, greater than 0.079λ, or greater than 0.036λ, respectively.

An acoustic wave device is disclosed. The acoustic wave device can include a piezoelectric layer positioned over a substrate. The acoustic wave device can also include an interdigital transducer electrode positioned over the piezoelectric layer. The acoustic wave device can also include a grounding structure positioned over the piezoelectric layer. The acoustic wave device can also include a conductive layer positioned under the substrate such that the substrate is positioned between the conductive layer and the grounding structure. The acoustic wave device can further include an electrical pathway that electrically connects the conductive layer to the grounding structure.

Acoustic resonator devices and filters are disclosed. A piezoelectric plate is attached to a substrate, a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A first conductor pattern is formed on a surface of the piezoelectric plate. The first conductor pattern includes interleaved fingers of an interdigital transducer disposed on the diaphragm, and a first plurality of contact pads. A second conductor pattern is formed on a surface of a base, the second conductor pattern including a second plurality of contact pads. Each pad of the first plurality of contact pads is connected to a respective pad of the second plurality of contact pads. A seal is formed between a perimeter of the piezoelectric plate and a perimeter of the base.

A high-frequency device includes: a circuit substrate including dielectric layers that are stacked, wiring patterns located on at least one of the dielectric layers, and a passive element formed of at least one of the wiring patterns, the circuit substrate having a first surface that is a surface of an outermost dielectric layer in a stacking direction of the dielectric layers; a terminal for connecting the high-frequency device to an external circuit, the terminal being located on the first surface and electrically connected to the passive element through a first path in the circuit substrate; and an acoustic wave element located on the first surface and electrically connected to the passive element through a second path in the circuit substrate.

A method of fabricating a bonded wafer with low carrier lifetime in silicon comprises providing a silicon substrate having opposing top and bottom surfaces, modifying a top portion of the silicon substrate to reduce carrier lifetime in the top portion relative to the carrier lifetime in portions of the silicon substrate other than the top portion, bonding a piezoelectric layer having opposing top and bottom surfaces separated by a distance T over the top surface of the silicon substrate, and providing a pair of electrodes having fingers that are inter-digitally dispersed on a top surface of the piezoelectric layer, the electrodes comprising a portion of a Surface Acoustic Wave (SAW) device. The modifying and bonding steps may be performed in any order. The modified top portion of the silicon substrate prevents the creation of a parasitic conductance within that portion during operation of the SAW device.

A multiplexer device includes a single die, at least three acoustic filters and at least one antenna port arranged on the single die, and a shunt inductance connected between each of the at least one antenna port and ground. Each acoustic filter includes one of a transmit or receive filter corresponding to a predetermined radio frequency band. The at least one antenna port is connected to at least one antenna, respectively, where each of the at least one antenna port is further connected to at least one acoustic filter arranged on the single die, and is configured to pass RF signals corresponding to the predetermined RF band of the connected at least one acoustic filter. The shunt inductance provides impedance matching between each of the at least one antenna port and each of the at least one acoustic filter connect to the at least one antenna port.

A first filter of a multiplexer includes a ladder filter structure with a plurality of series resonators and a plurality of parallel resonators. Each resonator is an acoustic wave resonator that includes an InterDigital Transducer (IDT) electrode including a pair of comb-shaped electrodes. A total number of reflection electrode fingers of the reflectors of at least one of the series resonator that is closest to the common terminal among the series resonators and the parallel resonator that is closest to the common terminal is smaller than a total number of reflection electrode fingers of the reflectors of each of a remainder of the resonators.

A surface acoustic wave resonator comprises interdigital transducer (IDT) electrodes disposed on an upper surface of a piezoelectric substrate between first and second reflector gratings each including reflector electrodes. The IDT electrodes include a central region having a first width in a direction perpendicular to an extension direction of the IDT electrodes and edge regions each having a second width on opposite sides of the central region. The IDT electrodes have a lesser average pitch in the central region than an average pitch of the IDT electrodes in each of the edge regions. The reflector electrodes have a lesser average pitch than the average pitch of the IDT electrodes in the central region.