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.

In a surface acoustic wave filter, a parallel arm resonator includes an IDT electrode and reflectors. Comb-shaped electrodes of the IDT electrode each include a busbar electrode and electrode fingers connected thereto, and are arranged so that the electrode fingers of the respective comb-shaped electrodes are alternately located in a propagation direction of a surface acoustic wave. The reflectors are provided on both sides of the IDT electrode portion in the propagation direction of the surface acoustic wave so that reflector electrode fingers are parallel or substantially parallel to the electrode fingers. A distance between the electrode finger and the reflector electrode finger which are proximate to each other is about 10% or more and about 20% or less of a main pitch of the electrode fingers.

A surface acoustic wave (SAW) resonator is provided with reduced rattling at frequencies lower than the resonance value. The SAW resonator includes an interdigital transducer (IDT) on a piezoelectric substrate. The IDT includes a first set of interdigital electrodes distributed between and parallel to the first end of the IDT and the second end of the IDT and a second set of interdigital electrodes interleaved with the first plurality of interdigital electrodes. A first resonant cavity is formed a predetermined distance from the first end of the IDT, and a second resonant cavity is formed a predetermined distance from the second end of the IDT. Additionally, a radio frequency (RF) filter is provided that includes multiple SAW resonators that include the resonant cavities formed a predetermined distance from the first and second ends of the IDT. This RF filter may provide increased bandwidth and reduced insertion loss.

A capacitive element includes a piezoelectric substrate, a first electrode finger extending towards a positive side in a first direction, and a second electrode finger disposed facing and spaced apart from the first electrode finger in a second direction intersecting the first direction, extending towards a negative side in the first direction, and connected to a different potential from the first electrode finger. The first electrode finger includes a first portion extending in the first direction and a second portion extending from the first portion, through a first step portion, and at a different position in the second direction from the first portion. The second electrode finger includes a third portion disposed facing the second portion and extending in the first direction, and a fourth portion extending from the third portion through a second step portion, extending from the second portion in the first direction, and facing the first portion.

An acoustic wave device comprises a substrate including a piezoelectric material, interdigital transducer (IDT) electrodes disposed on a surface of the substrate, a first dielectric film having a lower surface disposed on the IDT electrodes and the surface of the substrate, first strips formed of a first material having a density greater than a density of the first dielectric film disposed within the first dielectric film over tips of the interdigitated electrode fingers in the edge regions of the IDT electrodes, and second strips formed of a second material having a density greater than the density of the first dielectric film disposed within the first dielectric film in the gap regions of the IDT electrodes, laterally spaced from the first strips in a direction perpendicular to a direction of propagation of a main acoustic wave through the acoustic wave device, and extending only partially over the gap regions.

A delay compensation apparatus is provided, where a surface acoustic wave component is used as a main delay component for delay compensation. A size of the surface acoustic wave component is relatively small. Therefore, the delay compensation apparatus provided in embodiments of the present invention features a relatively small size and a relatively high device integration level.

A filter device having a pass band and a stop band on a lower frequency side than the pass band includes a filter having a pass band including the pass band, a series arm resonator connected in series to the filter, a first inductor directly connected in series to the series arm resonator, and a parallel arm resonator connected between a node on a path connecting the filter and the series arm resonator and the ground. The parallel arm resonator constitutes a resonance circuit having a resonant frequency at which an attenuation pole corresponding to a high frequency end of the first stop band, and the series arm resonator and the inductor constitute a resonance circuit having an anti-resonant frequency on a lower frequency side than the pass band and having a sub-resonant frequency higher than a resonant frequency of the resonance circuit.

An elastic wave device includes an interdigital transducer (IDT) electrode in contact with a piezoelectric substrate having a bus bar electrode region including one of a first bus bar electrode and a second bus bar electrode of the IDT electrode, an alternately disposed region where first electrode fingers are alternately disposed with second electrode fingers of the IDT electrode, and an intermediate region including one of the first electrode fingers and the second electrode fingers. A dielectric film is formed in at least part of the intermediate region and in contact with an upper surface of the IDT electrode. The dielectric film includes a medium in which an acoustic velocity of a transverse wave propagating in the dielectric film is lower than an acoustic velocity of a main elastic wave of the alternately disposed region. The dielectric film is not formed in the alternately disposed region.

An elastic wave resonator includes an interdigital transducer electrode provided on a piezoelectric substrate and including a first electrode layer made of Al or an alloy with Al as its primary component and including a first main surface on a side where the piezoelectric substrate is located and a second main surface on the opposite side from the first main surface. An SH wave is used as a propagated elastic wave. When a resonant frequency of the elastic wave resonator is fr and an anti-resonant frequency of the elastic wave resonator is fa, a minimum value of an absolute value of a distortion component in the first main surface calculated through a two-dimensional finite element method is about 1.4×10.sup.−3 or less at a frequency f expressed as:

f=fr+0.06×bw, where bw is fa−fr.

An elastic wave device includes a low acoustic velocity film, a piezoelectric film, and an IDT electrode, which are laminated on a high acoustic velocity material. In the IDT electrode, first electrode fingers, or second electrode fingers, or each of the first electrode fingers and the second electrode fingers, includes a wide width portion with a dimension in a width direction larger than a dimension at a center in a length direction and being provided closer to at least one of a side of a proximal end and a side of a distal end than a central region, at least one of a first busbar and a second busbar includes cavities arranged in a busbar length direction, and at least one of the first busbar and the second busbar includes an inner busbar portion which is positioned closer to a side of the first electrode fingers or a side of the second electrode fingers than the cavities are and which extends in the length direction of the first busbar and the second busbar, a central busbar portion that includes the cavities, and an outer busbar portion.