An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and reflectors. The interdigital transducer electrode includes first and second busbars including first and second cavities in a first direction, and first and second edge regions and first and second gap regions. The first and second edge regions include low acoustic velocity regions. Regions in which the first and second cavities are provided include high acoustic velocity regions. The reflector includes first and second reflector busbars and first reflection electrode fingers each including a second end portion that faces the second reflector busbar. The first reflection electrode fingers overlap the entire or substantially the entire second gap region when viewed in the first direction.

Radio frequency (RF) filtering devices, and particularly compensation structures for RF filtering devices are disclosed. Representative RF filtering devices are described that include compensation structures configured to adjust, reduce, or cancel leakage signals within the RF filtering devices, thereby providing improved isolation. Compensation structures may include surface acoustic wave (SAW) devices having multiple interdigital transducers (IDT) that are longitudinally coupled between two reflective structures. Different IDTs of a SAW device may be electrically connected to an RF filtering device, and at least one IDT of the SAW device may comprise an electrically floating electrode that provides the ability to further tune acoustic waves. Depending on the application, the compensation structure may be electrically connected to different portions of the RF filtering device. In certain embodiments, the RF filtering device is an RF duplexing device.

Radio frequency (RF) filtering devices, and particularly compensation structures for RF filtering devices are disclosed. Representative RF filtering devices are described that include compensation structures configured to adjust, reduce, or cancel leakage signals within the RF filtering devices, thereby providing improved isolation. Compensation structures may include surface acoustic wave (SAW) devices having multiple interdigital transducers (IDT) that are longitudinally coupled between two reflective structures. Different IDTs of a SAW device may be electrically connected to an RF filtering device, and at least one IDT of the SAW device may comprise an electrically floating electrode that provides the ability to further tune acoustic waves. Depending on the application, the compensation structure may be electrically connected to different portions of the RF filtering device. In certain embodiments, the RF filtering device is an RF duplexing device.

An acoustic wave device includes a piezoelectric substrate, an interdigital transducer electrode on the piezoelectric substrate, and reflectors. The interdigital transducer electrode includes first and second busbars including first and second cavities in a first direction, and first and second edge regions and first and second gap regions. The first and second edge regions include low acoustic velocity regions. Regions in which the first and second cavities are provided include high acoustic velocity regions. The reflector includes first and second reflector busbars and first reflection electrode fingers each including a second end portion that faces the second reflector busbar. The first reflection electrode fingers overlap the entire or substantially the entire second gap region when viewed in the first direction.

SAW element has a substrate; an IDT having a first comb-shaped electrode and a second comb-shaped electrode located on an upper surface of the substrate; and a capacitance element located on the upper surface of the substrate. The capacitance element has a first counter electrode connected to the first comb-shaped electrode and a second counter electrode connected to the second comb-shaped electrode and facing the first counter electrode across a third gaps. The direction from the first counter electrode through the third gaps toward the second counter electrode is a reverse direction from the direction from the first comb-shaped electrode through the gaps toward the second comb-shaped electrode. If it is assumed that the gap and width of the gap are d.sub.i and w.sub.i, and the gap and width of the third gap are D.sub.j and W.sub.j, the following formula holds:
0<(W.sub.j/D.sub.j.sup.2)<2(w.sub.i/d.sub.i.sup.2).

A structure of an acoustic wave filter includes: parallel resonators and series resonators, where the parallel resonators and the series resonators are cascaded; each of the parallel resonators includes a first supporting substrate, a first piezoelectric thin film, and a first electrode array; the first piezoelectric thin film is disposed on the first supporting substrate, and the first electrode array is disposed on the first piezoelectric thin film; the first electrode array includes a first interdigital electrode array and a first reflection grating array; and a quantity of pairs of first reflection gratings of at least one of the parallel resonators is less than or equal to a first preset threshold, and the first preset threshold is less than 5. The present disclosure can effectively suppress a fluctuation in a passband while ensuring high performance of the filter.