An acoustic wave device includes an IDT electrode on a piezoelectric substrate and reflector electrodes on both sides of the IDT electrode in an acoustic wave propagation direction and each including electrode fingers with gaps therebetween, and first dielectric films between the reflector electrodes and the piezoelectric substrate in regions where the electrode fingers and the gaps of the reflector electrodes are provided.

An acoustic wave device includes a piezoelectric substrate and an IDT electrode. The IDT electrode includes a center area and first and second edge areas. Areas including the first and second edge areas and overlapping the areas in an acoustic-wave propagation direction include first and second expansion edge areas. First and second acoustic-velocity adjusters are provided in the first and second expansion edge areas. The first and second acoustic-velocity adjusters respectively includes first and second end portions and third and fourth end portions. The first to fourth end portions are located at outer sides of the first and second edge areas. End portions in at least one of two pairs including a pair of first and third end portions and a pair of second and fourth end portions do not overlap each other in a direction in which electrode fingers extend.

An IDT electrode includes first and second busbar electrodes opposed to each other, first and second electrode fingers extending respectively from the first and second busbar electrodes on a piezoelectric substrate. The first busbar electrode and a tip end of the second electrode finger are opposed to each other with a gap therebetween, and bottom surfaces of the first and second busbar electrodes are opposed to each other with a first gap therebetween. The first and second busbar electrodes respectively include portions opposed to each other with a second gap shorter than the first gap therebetween on the top surface side. In a first area located between a first side surface and a second side surface, a second area located between the piezoelectric substrate and the first busbar electrode or the second electrode finger includes a hollow portion.

An acoustic wave device includes a piezoelectric layer, first and second upper electrodes, first and second lower electrodes, and first and second acoustic reflection films. In plan view, first and second resonator portions are respectively defined by portions where the first upper electrode and the first lower electrode overlap and where the second upper electrode and the second lower electrode overlap. The first and second acoustic reflection films respectively include first and second metal layers. First and second overlapping portions are respectively defined by portions where only the first upper electrode overlaps with the first metal layer and where only the second upper electrode overlaps with the second metal layer. An area of the first resonator portion is smaller than an area of the second resonator portion and an area of the first overlapping portion is larger than an area of the second overlapping portion.

An acoustic wave device, a method of manufacture of the same, and a radio frequency filter including the same. The acoustic wave device comprises a multilayer piezoelectric substrate (MPS) including a layer of piezoelectric material having a lower surface disposed on an upper surface of a layer of a dielectric material having a lower surface disposed on an upper surface of a carrier substrate. An interdigital transducer (IDT) is disposed on the multilayer piezoelectric substrate and includes an active region configured to generate an acoustic wave. First and second high impedance portions are included within the multilayer piezoelectric substrate, the first and second high impedance portions each positioned outside the active region of the interdigital transducer and extending in the direction of propagation of the acoustic wave to be generated by the interdigital transducer. The first and second high impedance portions reduce side leakage and suppress transverse modes.

An acoustic wave device includes a support substrate, a piezoelectric layer on the support substrate, and a functional element on the piezoelectric layer. The support substrate and the piezoelectric layer each have a rectangular or substantially rectangular shape in plan view from a direction normal to the support substrate. At least one corner portion of the piezoelectric layer has a curved shape or a polygonal shape.

An acoustic wave device includes an IDT electrode laminated on a piezoelectric substrate and defining a first resonator, and an IDT electrode laminated on the piezoelectric substrate and defining a second resonator. The first and second resonators are connected in parallel or in series. The IDT electrode of the first resonator includes an electrode layer including an epitaxial film and the IDT electrode of the second resonator includes an electrode layer including a non-epitaxial film.

An elastic wave device includes a piezoelectric substrate, an IDT electrode on the piezoelectric substrate, and a silicon oxide film arranged on the piezoelectric substrate to cover the IDT electrode. The IDT electrode includes first and second electrode layers laminated on each other, the first electrode layer is made of metal or an alloy with a density higher than a density of metal of the second electrode layer and a density of silicon oxide of the silicon oxide film, the piezoelectric substrate is made of LiNbO.sub.3 and θ is in a range of equal to or greater than about 8° and equal to or less than about 32° with Euler Angles (0°±5°, θ, 0°±10°) of the piezoelectric substrate, and the silicon oxide film contains hydrogen atoms, hydroxyl groups, or silanol groups.

A sensor system that combines the sensing application of surface acoustic wave (SAW) sensor and sensor signal transfer though the enclosure wall via acoustic means. The sensor system includes SAW sensor placed inside the enclosure and at least one pair of bulk acoustic wave (BAW) transducers, one mounted inside and second outside the enclosure wall, allowing the interrogation of SAW sensor from outside the enclosure. The external BAW transducer converts interrogation electrical pulse into acoustic pulse which travels though the enclosure wall to the internal BAW transducer. The internal BAW transducer converts the interrogation electrical pulse to electrical pulse and transfers it to SAW sensor. The response of the SAW transducer containing series of electric pulses is converted to the series of acoustic pulses by internal BAW transducer which propagates though enclosure wall. The external BAW transducer converts the series of acoustic pulses into series of electrical pulses and is received by the interrogation circuit for processing.

The present invention relates to a transducer structure with transverse mode suppression means, in particular for a single-port resonator, comprising a piezoelectric substrate (120, 170), at least a pair of inter-digitated comb electrodes (102, 112) formed on the piezoelectric substrate (120, 170), wherein the first comb electrode (102) comprises a first bus bar (108) and a plurality of electrode fingers (104) alternating with shorter dummy electrode fingers (106), both extending from the first bus bar (108), wherein the second comb electrode (112) comprises a second bus bar (118) and a plurality of electrode fingers (114) extending from the second bus bar (118), wherein the dummy electrode fingers (106) of the first bus bar (108) face the electrode fingers (114) of the second bus bar (118) and are separated from the electrode fingers (114) by first gaps (110a), characterized in further comprising a transverse mode suppression layer (122, 132, 222, 232, 422, 432) provided partially underneath the first gap (110a) and chosen such that the phase velocity of a guided wave is smaller in the region of the transverse mode suppression layer (122, 132, 222, 232, 422, 432) compared to the phase velocity of the guided wave in the central region (136) underneath the alternating electrodes fingers (104, 114) of the first and second electrodes (102, 112). The present invention also relates to a method for fabricating the transducer structure as previously described and to a single-port resonator comprising at least one structure as previously described.