An acoustic wave device is disclosed. The acoustic wave device can include a support substrate that includes a first substrate portion, a second substrate portion, and a third substrate portion between the first substrate portion and the second substrate portion. The acoustic wave device can also include a piezoelectric layer that includes a first portion over the first substrate portion and a second portion over the second substrate portion. The piezoelectric layer can be arranged such that a region over the third substrate portion is free from the piezoelectric layer. The acoustic wave device can also include a first interdigital transducer electrode on the first portion of the piezoelectric layer. The acoustic wave device can further include a second interdigital transducer electrode on the second portion of the piezoelectric layer.

A method of forming an acoustic wave device is disclosed. The method can include providing a structure having a support substrate that includes a first substrate portion, a second substrate portion, and a third substrate portion between the first portion and the second portion, a piezoelectric layer that includes a first portion over the first substrate portion and a second portion over the second substrate portion, a first interdigital transducer electrode on the first portion of the piezoelectric layer, and a second interdigital transducer electrode on the second portion of the piezoelectric layer. the method can also include etching at least a portion of the piezoelectric layer such that a region over the third substrate portion is free from the piezoelectric layer.

An acoustic wave device including series arm resonators including a first IDT electrode and parallel arm resonators including a second IDT electrode, in the first IDT electrode, a first envelope obliquely extends with respect to the acoustic wave propagation direction, and a second envelope obliquely extends with respect to the acoustic wave propagation direction, the second IDT electrode includes a central region, a first low acoustic velocity region in which an acoustic velocity is lower than an acoustic velocity in the central region, a second low acoustic velocity region in which an acoustic velocity is lower than the acoustic velocity in the central region, a first high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region, and a second high acoustic velocity region in which an acoustic velocity is higher than the acoustic velocity in the central region.

An acoustic wave device includes a piezoelectric layer made of lithium niobate or lithium tantalate, and at least one pair of electrodes opposed to each other in a direction intersecting a thickness direction of the piezoelectric layer. When d is a thickness of the piezoelectric layer and p is a distance between centers of electrodes adjacent to each other in the at least one pair of electrodes, d/p is about 0.5 or less. The at least one pair of electrodes extend in a longitudinal direction and includes a first electrode and a second electrode with sectional shapes different from each other in any cross section in a direction orthogonal or substantially orthogonal to the longitudinal direction of the at least one pair of electrodes.

There are disclosed acoustic resonators and method of fabricating acoustic resonators. An acoustic resonator includes a single-crystal piezoelectric plate having front and back surfaces, the back surface attached to a surface of a substrate except for portions of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern on the front surface includes an interdigital transducer (IDT) with interleaved fingers of the IDT disposed on the diaphragm. A periodic array of holes is provided in the diaphragm.

A first filter of a multiplexer has a ladder filter structure defined by acoustic wave resonators. An imaginary line obtained by connecting second ends of electrode fingers included in one comb-shaped electrode among a pair of comb-shaped electrodes of each resonator intersects a reference line that is a straight line extending in an acoustic wave propagation direction. When an angle defined by the reference line and the imaginary line of a first series resonator is represented by a first slant angle, an angle defined by the reference line and the imaginary line of a parallel resonator is represented by a second slant angle, and an angle defined by the reference line and the imaginary line of acoustic wave resonators is represented by a third slant angle, at least one of the first slant angle and the second slant angle is smaller than the third slant angle.

Certain aspects of the present disclosure provide an electroacoustic device and methods for signal processing via the electroacoustic device. One example electroacoustic device generally includes a first surface acoustic wave (SAW) resonator comprising a first apodized interdigital transducer (IDT) disposed between a first busbar and a second busbar, and a second SAW resonator comprising a second apodized IDT disposed between the second busbar and a third busbar, wherein the second busbar is at an angle with respect to at least one of the first busbar or the third busbar.

A first filter of a multiplexer includes a ladder filter structure of acoustic wave resonators. An imaginary line obtained by connecting second ends of electrode fingers included in one comb-shaped electrode among a pair of comb-shaped electrodes of each resonator intersects a reference line that is a straight line extending in an acoustic wave propagation direction. When an angle defined by the reference line and the imaginary line of a first series resonator is represented by a first slant angle, an angle defined by the reference line and the imaginary line of a parallel resonator is represented by a second slant angle, and an angle defined by the reference line and the imaginary line of acoustic wave resonators is represented by a third slant angle, at least one of the first slant angle and the second slant angle is larger than the third slant angle.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode on the piezoelectric substrate. The IDT electrode includes a first busbar and a second busbar that oppose each other, multiple first electrode fingers, multiple second electrode fingers, multiple first offset electrodes, and multiple second offset electrodes. A virtual line connecting the leading ends of the first electrode fingers is referred to as a first envelope. The first envelope is included relative to the acoustic-wave propagation direction. A virtual line connecting the leading ends of the second electrode fingers is referred to as a second envelope. The second envelope is inclined relative to the acoustic-wave propagation direction. The direction in which the first offset electrodes extend and the direction in which the second offset electrodes extend inclined relative to the direction orthogonal or substantially orthogonal to the acoustic-wave propagation direction.

A focusing interdigital transducer (IDT) and corresponding single- and dual-port piezoelectric devices are disclosed. The focusing interdigital transducer, which generates Lam acoustic waves, permits operation at significantly higher frequencies than those possible with traditional IDTs. The focusing IDT employs multiple arced fingers formed both above and below the piezoelectric layer to improve coupling efficiency by coupling through both the e.sub.31 and e.sub.33 piezoelectric coefficients to the piezoelectric layer. By optimizing both anchor design and location, acoustic wave losses are minimized, thereby improving the device's quality factor Q. Through proper bus design and selection of the number of IDT fingers, a device's impedance can be tuned for a given application. The focusing IDTs may be used in single-port filter devices and dual-port transformer devices. The single- and dual-port devices may operate at a single frequency, at two frequencies, or over a band of frequencies.