Nonlinear acoustic media and related methods are described herein. The nonlinear acoustic media are configured to generate higher harmonic output signals from a single-frequency input signal. The higher harmonic output signals can be generated through the coupling of an acoustic dielectric medium to a nonlinear piezoelectric medium having four ports.

Techniques for improving Bulk Acoustic Wave (BAW) reflector and resonator structures are disclosed, including filters, oscillators and systems that may include such devices. A Bulk Acoustic Wave (BAW) resonator of this disclosure may comprise a substrate and an active piezoelectric resonant volume. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may have a main resonant frequency. The active piezoelectric resonant volume of the Bulk Acoustic Wave (BAW) resonator may comprise first and second piezoelectric layers having respective piezoelectric axis that substantially oppose one another. A first patterned layer may be disposed within the active piezoelectric volume. This may, but need not facilitate suppression of spurious modes. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in a super high frequency (SHF) band. The main resonant frequency of the Bulk Acoustic Wave (BAW) resonator may be in an extremely high frequency (EHF) band.

A transducer structure for a surface acoustic device comprises a composite substrate comprising a piezoelectric layer, a pair of inter-digitated comb electrodes, comprising a plurality of electrode means with a pitch p satisfying the Bragg condition, wherein the inter-digitated comb electrodes are embedded in the piezoelectric layer such that, in use, the excitation of a wave propagating mode in the volume of the electrode means is taking place and is the predominant propagating mode of the structure. The present disclosure relates also to an acoustic wave device comprising at least one transducer structure as described above and to a method for fabricating the transducer structure. The present disclosure relates also to the use of the frequency of the bulk wave propagating in the electrode means of the transducer structure in an acoustic wave device to generate contribution at high frequency, in particular, above 3 GHz.

A resonator is provided that includes a vibrating section that vibrates in a contour vibration mode, a frame that surrounds at least a portion of the vibrating section, supporting sections extending along a Y-axis direction and connecting the vibrating section and the frame. The vibrating section includes a through hole that extends along an X-axis direction perpendicular to the Y-axis direction such that a coupling section is disposed between the through hole and each of the supporting sections. The length SL of the through hole in the X-axis direction is longer than the length Sd of the coupling section in the Y-axis direction.

Bulk acoustic wave resonators are presented. Such resonators typically operate based on a dynamic nonuniform effective piezoelectricity in composite multilayer ferroelectrics with large electrostriction coefficients, like barium strontium titanate (BST). Harmonic resonance modes of a multilayer bulk acoustic wave resonator can be selectively excited with an electromechanical coupling coefficient equal to the fundament mode, which is contrary to the trend K2∝1/n2 exhibited by conventional piezoelectric bulk acoustic resonators. Such a resonator allows for the design of a new class of band-switching filters.

Techniques for improving Bulk Acoustic Wave (BAW) reflector and resonator structures are disclosed, including filters, 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 having a first piezoelectric axis orientation. The bulk acoustic wave (BAW) resonator may comprise a multi-layer acoustic reflector, e.g., a multi-layer metal top acoustic reflector electrode, including a first pair of top metal electrode layers. The first pair of top metal electrode layers may be electrically and acoustically coupled with the first layer of piezoelectric material to excite a piezoelectrically excitable resonance mode at a resonant frequency of the BAW resonator.

Techniques for improving acoustic wave device structures are disclosed, including filters and systems that may include such devices. An apparatus may comprise a first electrical filter including an acoustic wave device. The first electrical may having a first filter band in a Super High Frequency (SHF) band or an Extremely High Frequency (EHF) band to facilitate compliance with a regulatory requirement or a standards setting organization specification. For example, the first electrical filter may comprise a notch filter having a notch band overlapping at least a portion of an Earth Exploration Satellite Service (EESS) band to facilitate compliance with a regulatory requirement or the standards setting organization specification for the Earth Exploration Satellite Service (EESS) 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.

Techniques for improving Bulk Acoustic Wave (BAW) resonator 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 opposes the first piezoelectric axis orientation of the first layer of piezoelectric material. A top acoustic reflector including a first pair of top metal electrode layers may be electrically and acoustically coupled with the first layer of piezoelectric material to excite the piezoelectrically excitable main resonance mode at a resonant frequency.

A transducer structure for a surface acoustic device comprises a composite substrate comprising a piezoelectric layer, a pair of inter-digitated comb electrodes, comprising a plurality of electrode means with a pitch p satisfying the Bragg condition, wherein the inter-digitated comb electrodes are embedded in the piezoelectric layer such that, in use, the excitation of a wave propagating mode in the volume of the electrode means is taking place and is the predominant propagating mode of the structure. The present disclosure relates also to an acoustic wave device comprising at least one transducer structure as described above and to a method for fabricating the transducer structure. The present disclosure relates also to the use of the frequency of the bulk wave propagating in the electrode means of the transducer structure in an acoustic wave device to generate contribution at high frequency, in particular, above 3 GHz.