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.

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.

An acoustic wave device includes a piezoelectric substrate, and an IDT electrode on the piezoelectric substrate. The piezoelectric substrate includes a high acoustic velocity layer, and a piezoelectric layer. The IDT electrode includes a first busbar and a second busbar, and first and second electrode fingers interdigitated with each other. A first envelope and a second envelope each extend in a slanted direction with respect to an acoustic wave propagation direction, the first envelope being an imaginary line formed by connecting tips of the first electrode fingers, the second envelope being an imaginary line formed by connecting tips of the second electrode fingers. The first dielectric film is located in at least one gap of first and second gaps, the first gaps being located between the first electrode fingers and the second busbar, the second gaps being located between the second electrode fingers and the first busbar. The first dielectric film has a density greater than a density of silicon oxide.

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.

In a filter device, a transversal elastic wave filter, which defines a delay element, is connected in parallel with a band pass filter. The transversal elastic wave filter has the same amplitude characteristic as and the opposite phase to the band pass filter at a desired frequency inside an attenuation range of the band pass filter. When a wavelength determined by an electrode finger period of IDTs and is denoted by , the distance between the first IDT and the second IDT of the elastic wave filter is about 12 or less.

A filter body has a series arm including a plurality of series resonators connected in series with one another and one or more parallel resonators in such a manner that the series arm and the parallel resonators are connected in a ladder form. The series arm has a bent part, and when viewed from an elastic wave propagation direction, a series resonator located closest to a first terminal from a circuit perspective among the plurality of series resonators and a parallel resonator located closest to the first terminal from a circuit perspective among the plurality of parallel resonators do not overlap a series resonator located closest to a second terminal from a circuit perspective among the plurality of series resonators and a parallel resonator located closest to the second terminal from a circuit perspective among the plurality of parallel resonators.

In a filter device, a transversal elastic wave filter, which defines a delay element, is connected in parallel with a band pass filter. The transversal elastic wave filter has the same amplitude characteristic as and the opposite phase to the band pass filter at a desired frequency inside an attenuation range of the band pass filter. When a wavelength determined by an electrode finger period of IDTs and is denoted by , the distance between the first IDT and the second IDT of the elastic wave filter is about 12 or less.

A device includes a die and an interdigital transducer on the die. The interdigital transducer includes a first bus bar, a second bus bar, and a number of electrode fingers. The first bus bar is parallel to the second bus bar. The electrode fingers are divided into a first set of electrode fingers and a second set of electrode fingers. The first set of electrode fingers extend obliquely from the first bus bar towards the second bus bar. The second set of electrode fingers extend obliquely from the second bus bar towards the first bus bar, and are parallel to and interleaved with the first set of electrode fingers. By providing the electrode fingers oblique to the bus bars, spurious transverse modes may be suppressed while maintaining the quality factor, electromechanical coupling coefficient, and capacitance of the device.

A laterally coupled resonator filter device includes a bottom electrode, a piezoelectric layer disposed on the bottom electrode, and a top contour electrode disposed on the piezoelectric layer. The top contour electrode includes first and second top comb electrodes. The first top comb electrode include a first top bus bar and multiple first top fingers extending in a first direction from the first top bus bar. The second top comb electrode includes a second top bus bar and multiple second top fingers extending in a second direction from the second top bus bar, the second direction being substantially opposite to the first direction such that the first and second top fingers form a top interleaving pattern providing an acoustic filter having an apodized shape.

In a filter device, a transversal elastic wave filter, which defines a delay element, is connected in parallel with a band pass filter. The transversal elastic wave filter has the same amplitude characteristic as and the opposite phase to the band pass filter at a desired frequency inside an attenuation range of the band pass filter. When a wavelength determined by an electrode finger period of IDTs and is denoted by , the distance between the first IDT and the second IDT of the elastic wave filter is about 12 or less.