An acoustic wave device includes a piezoelectric layer and an interdigital electrode structure over the piezoelectric layer. The interdigital electrode structure includes a plurality of first electrode fingers extending from a first busbar towards a first apodization edge, and a plurality of second electrode fingers extending from a second busbar towards a second apodization edge. The plurality of first electrode fingers and the plurality of second electrode fingers are interleaved with one another. At least one of the first apodization edge or the second apodization edge follows a periodic arccosine apodization function over at least two adjacent electrode fingers. A number of periods of the first apodization edge or the second apodization edge is at least 2. A first distance between one of a first electrode finger or a second electrode finger and the respective periodic arccosine apodization function is less than or equal to a predetermined percentage of an apodization amplitude.

A wireless temperature sensor based chip comprises: an interdigital transducer, reflecting gratings, and a piezoelectric substrate. The interdigital transducer and the reflecting gratings are disposed on the piezoelectric substrate. The reflecting gratings are symmetrically disposed at two sides of the interdigital transducer. The interdigital transducer, the reflecting gratings, and the piezoelectric substrate are disposed in a housing of the sensor. Strips of the interdigital transducer vary from left to right in a grade-changing weighted manner, that is, overlapped lengths between adjacent strips vary from left to right according to a cosine function. The reflecting gratings use a metal aperture weighted manner, that is, the metal aperture is disposed between strips of the reflecting gratings. The temperature sensor based chip requires no power supply and transmission lines, can implement temperature measurement with high precision in a harsh environment.

A wireless temperature sensor based chip comprises: an interdigital transducer, reflecting gratings, and a piezoelectric substrate. The interdigital transducer and the reflecting gratings are disposed on the piezoelectric substrate. The reflecting gratings are symmetrically disposed at two sides of the interdigital transducer. The interdigital transducer, the reflecting gratings, and the piezoelectric substrate are disposed in a housing of the sensor. Strips of the interdigital transducer vary from left to right in a grade-changing weighted manner, that is, overlapped lengths between adjacent strips vary from left to right according to a cosine function. The reflecting gratings use a metal aperture weighted manner, that is, the metal aperture is disposed between strips of the reflecting gratings. The temperature sensor based chip requires no power supply and transmission lines, can implement temperature measurement with high precision in a harsh environment.

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.

An acoustic wave device includes a piezoelectric substrate, a first interdigital transducer (IDT) electrode, reflectors on both sides of the first IDT electrode in a propagation direction of an acoustic wave, and a second IDT electrode facing the first IDT electrode with a reflector interposed therebetween. The first and second IDT electrodes include first and second intersecting areas in which electrode fingers overlap in the propagation direction. The first and second intersecting areas overlap in the propagation direction. A third busbar of the second IDT electrode is coupled to a first busbar of the first IDT electrode. A fourth busbar of the second IDT electrode is coupled to a ground potential. A resonant frequency of the second IDT electrode is in a frequency band of an interference wave signal.

Surface acoustic wave (SAW) structures with transverse mode suppression are disclosed. In one aspect, the SAW structure provides digits or fingers with broad interior terminal end shapes. By providing such shapes spurious modes above the resonance frequency of the SAW are suppressed thereby providing desired out of band rejection that helps satisfy design criteria such as keeping a higher Q value, a higher K2 value and better Temperature Coefficient of Frequency (TCF).

A tunable filter using Love waves includes an inductance for band extension connected to each of piezoelectric resonators, variable capacitances are connected to the piezoelectric resonator, the piezoelectric resonators each include a LiNbO.sub.3 substrate and an IDT electrode, and a pass band and an attenuation region are positioned in a frequency region on a lower frequency side relative to a value obtained by a calculation in which an acoustic velocity of a low-velocity transversal wave propagating in the LiNbO.sub.3 substrate is divided by a wave length defined by a period of the IDT electrode.

An acoustic resonator includes a piezoelectric layer on a substrate and an interdigital electrode structure on the piezoelectric layer. The interdigital electrode structure includes a first bus bar, a second bus bar, a first set of electrode fingers, and a second set of electrode fingers. The first bus bar and the second bus bar extend parallel to one another along a length of the interdigital electrode structure. The first set of electrode fingers are coupled to the first bus bar and extend to a first apodization edge. The second set of electrode fingers are coupled to the second bus bar and extend to a second apodization edge. The first set of electrode fingers and the second set of electrode fingers are interleaved. At least one of the first apodization edge and the second apodization edge provides a wave pattern along the length of the interdigital electrode structure.

An elastic wave resonator including a pair of comb-shaped electrodes and a pair of reflector electrodes formed on a piezoelectric substrate. In one example, the pair of comb-shaped electrodes includes first and second overlapping regions in which electrode fingers of the comb-shaped electrodes interdigitate, the second overlapping region being provided on both outside edges of the first overlapping region in an overlapping width direction, an overlapping width of the first overlapping region being greater than an overlapping width of the second overlapping region, the pair of comb-shaped electrodes being configured to excite a first elastic wave in the first overlapping region and to excite a second elastic wave in the second overlapping region, a frequency of the first elastic wave being higher than a frequency of the second elastic wave.

An acoustic wave device includes: a piezoelectric substrate; a comb-shaped electrode that is located on the piezoelectric substrate and excites an acoustic wave; and a silicon oxide film that is located on the piezoelectric substrate so as to cover the comb-shaped electrode, and has a total concentration of carbon (C), hydrogen (H), nitrogen (N), and fluorine (F) equal to or less than 3.5 atomic %.