A method of manufacturing a piezoelectric resonator unit that includes mounting a piezoelectric resonator on a base member using a conductive adhesive, keeping the piezoelectric resonator in an environment having a temperature and a humidity higher than those of a surrounding region for a predetermined time, performing frequency adjustment of the piezoelectric resonator by etching using an ion beam, and joining a lid member to the base member using a joining material such that the piezoelectric resonator is hermetically sealed between the lid member and the base member.

A piezoelectric vibration member that includes a substrate having a main surface on or in which a piezoelectric vibration member is mounted, a lid having a recess that is open so as to face the main surface and which includes a flange portion that projects outward from an opening edge of the recess, and a bonding layer that bonds the substrate and the lid together so as to hermetically seal the piezoelectric vibrator in a space between the recess and the main surface. The surface roughness of a side surface of the flange portion is greater than the surface roughness of the surface of the recess, and the bonding layer extends from the main surface of the substrate to the side surface of the flange portion.

In an array of single crystal acoustic resonators, the effective coupling coefficient of first and second strained single crystal filters are individually tailored in order to achieve desired frequency responses. In a duplexer embodiment, the effective coupling coefficient of a transmit band-pass filter is lower than the effective coupling coefficient of a receive band-pass filter of the same duplexer. The coefficients can be tailored by varying the ratio of the thickness of a piezoelectric layer to the total thickness of electrode layers or by forming a capacitor in parallel with an acoustic resonator within the filter for which the effective coupling coefficient is to be degraded. Further, a strained piezoelectric layer can be formed overlying a nucleation layer characterized by nucleation growth parameters, which can be configured to modulate a strain condition in the strained piezoelectric layer to adjust piezoelectric properties for improved performance in specific applications.

Provided are a resonator, a method of manufacturing the resonator, and a strain sensor and a sensor array including the resonator. The resonator is provided to extend in a lengthwise direction from a support. The resonator includes a single crystal material and is provided to extend in a crystal orientation that satisfies at least one from among a Young's modulus and a Poisson's ratio, from among crystal orientations of the single crystal material.

A method for manufacturing a piezoelectric vibration element that includes preparing a piezoelectric substrate; providing a first electrode layer on a first main surface of the piezoelectric substrate; arranging a mask on a side of the first main surface of the piezoelectric substrate, the mask including a center region and a peripheral region located along a periphery of the center region; and irradiating a radiation beam through the mask toward the first main surface of the piezoelectric substrate such that a larger amount of the radiation beam passes through the peripheral region than the center region of the mask so as to remove a part of the first electrode layer to form a first excitation electrode that decreases in thickness from the center region to the peripheral region of the mask on the first main surface of the piezoelectric substrate.

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 method for manufacturing a quartz crystal resonator that includes a quartz crystal blank having a vibrating portion including a center of a principal surface of the quartz crystal blank when viewed in plan from a direction normal to the principal surface and a peripheral portion adjacent to the vibrating portion, a pair of excitation electrodes disposed opposite to each other with the vibrating portion interposed therebetween, a pair of electrode pads disposed on the peripheral portion, and a pair of extended electrodes each extending from the vibrating portion to the peripheral portion to electrically connect one excitation electrode to a corresponding electrode pad, where the method includes conducting a first trimming of the vibrating portion and the peripheral portion; and conducting a second trimming of part of one of the excitation electrodes on the vibrating portion.

Techniques for improving acoustic wave device structures are disclosed, including filters, oscillators and systems that may include such devices. First and second layers of piezoelectric material may be acoustically coupled with one another to have a piezoelectrically excitable resonance mode. The first layer of piezoelectric material may have a first piezoelectric axis orientation, and the second layer of piezoelectric material may have a second piezoelectric axis orientation that substantially opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. The first and second layers of piezoelectric material have respective thicknesses so that the acoustic wave device has a resonant frequency that is in a super high frequency band or an extremely high frequency band.

Techniques for improving Bulk Acoustic Wave (BAW) resonator structures are disclosed, including fluidic systems, oscillators and systems that may include such devices. A bulk acoustic wave (BAW) resonator may comprise a substrate and a first layer of piezoelectric material. The bulk acoustic wave (BAW) resonator may comprise a top electrode. A sensing region may be acoustically coupled with the top electrode of the bulk acoustic wave (BAW) resonator.

A bulk acoustic wave (BAW) device comprises a piezoelectric layer disposed between a first electrode layer and a sandwich electrode. The sandwich electrode includes a first layer of a first material having a first acoustic impedance and a second layer of a second material having a second acoustic impedance that is less than the first acoustic impedance of the first layer. The second layer of the sandwich electrode having the lower acoustic impedance is disposed between the first layer and the piezoelectric layer. The sandwich electrode combined with the piezoelectric layer and first electrode can cause the BAW device to resonate at a frequency whose wavelength corresponds to an acoustic cavity length of the BAW device, depending on an acoustic mirror included on one side of the BAW device. In one example, the acoustic cavity length is about 1.5 times of the resonant frequency wavelength.