An acoustic wave device includes first and second acoustic wave resonators with first and second IDT electrodes on a common piezoelectric substrate. A first apodization area in the first IDT electrode includes first and second edge areas with a first center area therebetween. A second apodization area in the second IDT electrode includes third and fourth edge areas with a second center area therebetween. At least one first mass-adding film is located in at least one of the first and second edge areas and overlaps the electrode fingers of the first IDT electrode, and at least one second mass-adding film is located in at least one of the third and fourth edge areas and overlaps the electrode fingers of the second IDT electrode. A thickness of the at least one first mass-adding film is equal to a thickness of the at least one second mass-adding film.

An acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode disposed over the piezoelectric layer. The interdigital transducer electrode is thicker in a center region of the interdigital transducer electrode than in a gap region of the interdigital transducer electrode to thereby reduce a mass loading of the interdigital transducer electrode in the gap region. The interdigital transducer electrode has a layer of less dense material disposed of a layer of more dense material.

An acoustic wave device includes a piezoelectric layer and an IDT electrode. The IDT electrode includes first and second busbars, and first and second electrode fingers interdigitated with each other. A virtual line connecting ends of the second electrode fingers is defined as a first envelope, a virtual line connecting ends of the first electrode fingers is defined as a second envelope, and a region between the first and second envelopes is an intersection region. Shapes of the first and second electrode fingers include at least two curved portions different from each other in the intersection region. In the intersection region, a value of at least one of a duty ratio, an electrode finger pitch, and thicknesses of the first and second electrode fingers changes in one of a direction in which the value increases and the direction in which the value decreases.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a multi-layer mass loading strip. The mass loading strip has a density that is higher than a density of the temperature compensation layer. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can include a first layer for adhesion and a second layer for mass loading. The mass loading strip can suppress a transverse mode.

An acoustic wave device includes a high acoustic velocity material layer, a piezoelectric layer including lithium tantalate, and an IDT on the piezoelectric layer and including electrode finger portions each including at least one electrode finger portion layer. An acoustic velocity of a bulk wave propagating in the high acoustic velocity material layer is higher than that in the piezoelectric layer. T.sub.R=(1/3.15) (T.sub.m/T.sub.IDT)100 [%] is satisfied, where T.sub.R is a value obtained by dividing a thickness ratio of an Al-equivalent normalized thickness T.sub.m of a mass addition film relative to an Al-equivalent normalized thickness T.sub.IDT of the electrode finger portion by about 3.15. A wavelength ratio width and a thickness ratio have values within a range on an ellipse and inside of the ellipse on an xy plane expressed by:

x=0.19cos(5.5)cos

0.021sin(5.5)sin +0.0146T.sub.IDT.sup.20.229T.sub.IDT+1.5611+0.4(d0.55),

and

y=0.19sin(5.5)cos +0.021cos(5.5)sin +10.15.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

An acoustic wave filter includes a piezoelectric layer. A first acoustic wave device includes a portion of the piezoelectric layer and a first multi-layer interdigital transducer electrode disposed over the first portion of the piezoelectric layer. Additional acoustic wave devices are coupled to the first acoustic wave device, the additional acoustic wave devices including a second portion of the piezoelectric layer and a plurality of multi-layer interdigital transducer electrodes disposed over the second portion of the piezoelectric layer. At least one of the plurality of multi-layer interdigital transducer electrodes includes a layer that is thinner than a corresponding layer of the same material of the first multi-layer interdigital transducer electrode of the first acoustic wave device.

An acoustic wave device includes a piezoelectric substrate and an interdigital transducer disposed on the piezoelectric substrate, the interdigital transducer including a center region, first and second edge regions, and first and second gap regions, a temperature compensation layer covering the interdigital transducer, and a floating metal layer buried in the temperature compensation layer or disposed on top of the temperature compensation layer. The floating metal layer includes a plurality of floating metal blocks spaced apart from each other and overlapping at least the first and second edge regions of the interdigital transducer.

Aspects of this disclosure relate to an acoustic wave device with transverse mode suppression. The acoustic wave device can include a piezoelectric layer, an interdigital transducer electrode, a temperature compensation layer, and a mass loading strip. The mass loading strip can overlap edge portions of fingers of the interdigital transducer electrode. The mass loading strip can have a sidewall that is tapered inwardly from a bottom side of the mass loading strip to a top side of the mass loading strip. The top side can be shorter than the bottom side.

An acoustic wave device includes a piezoelectric layer and an interdigital transducer electrode disposed over the piezoelectric layer. The interdigital transducer electrode is thicker in a center region of the interdigital transducer electrode than in a gap region of the interdigital transducer electrode to thereby reduce a mass loading of the interdigital transducer electrode in the gap region. The interdigital transducer electrode has a layer of more dense material disposed of a layer of less dense material.