Abstract: An elastic wave device that achieves an improved frequency-temperature characteristic and a sufficiently reduced spurious component includes a piezoelectric body including a LiNbO3 substrate, a first dielectric layer including a SiO2 layer, a second dielectric layer, and IDT electrodes disposed at an interface between the piezoelectric body and the first dielectric layer. Each of the IDT electrodes includes a multilayer structure in which a first electrode film including at least one layer including Pt or a Pt-based alloy and a second electrode film including Al or an Al-based alloy are provided. ? and ? of Euler angles (?, ?, ?) of the LiNbO3 substrate are in the range of ?=0±about 2° and the range of about 80°???about 130°, respectively. ? is in the range of about 5°???about 30°. The normalized thickness h/? and ? satisfy the following expression: h/?×100?about 0.0019×?2+about 0.0115×?+3.0.

Abstract: An inexpensive compact band rejection filter realizes a high sharpness of a filter characteristic at ends of passbands and has a large attenuation. In the band rejection filter, at least one of a plurality of elastic wave resonators, which contributes to formation of a transition band, has a propagation angle larger than those of the other elastic wave resonators. Accordingly, the at least one of the plurality of elastic wave resonators which contributes to the formation of the transition band has an electromechanical coupling coefficient that is smaller than electromechanical coupling coefficients of the other elastic wave resonators.

Abstract: A boundary acoustic wave device includes a piezoelectric substance made of LiNbO3 having a surface obtained by rotating a Y axis by about 15°±10° as a primary surface, a dielectric substance which is made of a silicon oxide and which is laminated to the piezoelectric substance, and an electrode structure disposed at a boundary between the piezoelectric substance and the dielectric substance and which includes an IDT arranged to utilize a boundary acoustic wave propagating along the boundary. When the density of the IDT, the thickness thereof, the wavelength deter-mined by the period of electrode fingers of the IDT, and the duty ratio thereof are represented by ? (kg/m3), H (?m), ? (?m), and x, respectively, x and the product of H/? and ? are set in a range that satisfies the following formula (1): (H/?)×?>70.7924(x+0.055)(?2.884)+797.09??Formula (1).

Abstract: A boundary acoustic wave filter device capable of increasing an out-of-band attenuation includes a dielectric film formed on a piezoelectric substrate, at least one longitudinally coupled resonator boundary acoustic wave filter having a plurality of IDTs disposed along a boundary between the piezoelectric substrate and the dielectric film, and at least two one-terminal-pair boundary acoustic wave resonators. At least one boundary acoustic wave resonator is connected in series to the longitudinally coupled resonator boundary acoustic wave filter, and at least remaining one boundary acoustic wave resonator is connected in parallel to the longitudinally coupled resonator boundary acoustic wave filter.

Abstract: A boundary acoustic wave device includes a piezoelectric substance made of LiNbO3 having a surface obtained by rotating a Y axis by about 15°±10° as a primary surface, a dielectric substance which is made of a silicon oxide and which is laminated to the piezoelectric substance, and an electrode structure which is disposed at a boundary between the piezoelectric substance and the dielectric substance and which includes an IDT arranged to utilize a boundary acoustic wave propagating along the boundary. When the density of the IDT, the thickness thereof, the wavelength determined by the period of electrode fingers of the IDT, and the duty ratio thereof are represented by ? (kg/m3), H (?m), ?(?m), and x, respectively, x and the product of H/? and ? are set in a range that satisfies the following formula (1): (H/?)×?>70.7924(x+0.055)(?2.0884)+797.09??Formula (1).

Abstract: A boundary acoustic wave filter device capable of increasing an out-of-band attenuation includes a dielectric film formed on a piezoelectric substrate, at least one longitudinally coupled resonator boundary acoustic wave filter having a plurality of IDTs disposed along a boundary between the piezoelectric substrate and the dielectric film, and at least two one-terminal-pair boundary acoustic wave resonators. At least one boundary acoustic wave resonator is connected in series to the longitudinally coupled resonator boundary acoustic wave filter, and at least remaining one boundary acoustic wave resonator is connected in parallel to the longitudinally coupled resonator boundary acoustic wave filter.

Abstract: A surface acoustic wave (SAW) filter includes a piezoelectric substrate. A resin pattern having a permittivity less than that of the piezoelectric substrate and first and second conductor patterns are disposed on the piezoelectric substrate. The first conductor pattern defines two one-terminal-pair SAW resonators and two longitudinally coupled resonator SAW filters. A portion of the second conductor pattern defines wiring traces having different potentials. Portions of the wiring traces facing each other in a plan view are disposed on the resin pattern.

Abstract: A surface acoustic wave device includes first stage longitudinally coupled resonator type surface acoustic wave elements and second stage longitudinally coupled resonator type surface acoustic wave elements that are cascaded to each other and are arranged on a piezoelectric substrate. Each of the first and second stage longitudinally coupled resonator type surface acoustic wave elements is provided with at least three IDTs arranged along the direction of transmission of a surface acoustic wave. The central IDT of each of the longitudinally coupled resonator type surface acoustic wave elements includes narrow pitch electrode finger portions. At least one of the number and the pitch of the electrode fingers of the narrow pitch electrode finger portions of the first stage longitudinally coupled resonator type surface acoustic wave elements is set to be different from that of the second stage longitudinally coupled resonator type surface acoustic wave elements.

Abstract: A surface acoustic wave filter has one or more surface acoustic wave filter elements having at least two comb-shaped electrode portions disposed along a propagation direction of a surface acoustic wave and first and second balanced terminals connected to the comb-shaped electrode portions provided on a piezoelectric substrate. The surface acoustic wave filter is housed in a packaging member such that the difference in capacitance between electrodes on the piezoelectric substrate, which are connected to the first and second balanced terminals, is greatly reduced.

Abstract: A surface acoustic wave device includes first stage longitudinally coupled resonator type surface acoustic wave elements and second stage longitudinally coupled resonator type surface acoustic wave elements that are cascaded to each other and are arranged on a piezoelectric substrate. Each of the first and second stage longitudinally coupled resonator type surface acoustic wave elements is provided with at least three IDTs arranged along the direction of transmission of a surface acoustic wave. The central IDT of each of the longitudinally coupled resonator type surface acoustic wave elements includes narrow pitch electrode finger portions. At least one of the number and the pitch of the electrode fingers of the narrow pitch electrode finger portions of the first stage longitudinally coupled resonator type surface acoustic wave elements is set to be different from that of the second stage longitudinally coupled resonator type surface acoustic wave elements.

Abstract: A surface acoustic wave (SAW) filter includes a piezoelectric substrate. A resin pattern having a permittivity less than that of the piezoelectric substrate and first and second conductor patterns are disposed on the piezoelectric substrate. The first conductor pattern defines two one-terminal-pair SAW resonators and two longitudinally coupled resonator SAW filters. A portion of the second conductor pattern defines wiring traces having different potentials. Portions of the wiring traces facing each other in a plan view are disposed on the resin pattern.

Abstract: A surface acoustic wave filter has one or more surface acoustic wave filter elements having at least two comb-shaped electrode portions disposed along a propagation direction of a surface acoustic wave and first and second balanced terminals connected to the comb-shaped electrode portions provided on a piezoelectric substrate. The surface acoustic wave filter is housed in a packaging member such that the difference in capacitance between electrodes on the piezoelectric substrate, which are connected to the first and second balanced terminals, is greatly reduced.