Abstract: A method for adjusting a frequency characteristic of an edge reflection type surface acoustic wave device includes the step of obtaining a frequency characteristic of an edge reflection type surface acoustic wave device having a piezoelectric substrate. The edge reflection type surface acoustic wave device has a pair of edges of the piezoelectric substrate which define a predetermined distance therebetween. The piezoelectric substrate is cut at a position which defines a distance that is shorter than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be higher than the obtained frequency characteristic. The piezoelectric substrate is cut at a position which defines a distance that is longer than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be lower than the obtained frequency characteristic.

Abstract: An edge reflection surface acoustic wave filter includes IDTs disposed on a top surface of a piezoelectric substrate, and surface acoustic waves of the Shear Horizontal type are reflected between opposite edges. At least one outermost electrode finger in the direction of propagation of surface acoustic waves on the side of at least one of the edges is removed. Accordingly, desired filter characteristics can readily be achieved without causing variations in filter characteristics, spurious components at frequencies lower than the passband are minimized, and selectivity is greatly improved.

Abstract: A method for adjusting a frequency characteristic of an edge reflection type surface acoustic wave device includes the step of obtaining a frequency characteristic of an edge reflection type surface acoustic wave device having a piezoelectric substrate. The edge reflection type surface acoustic wave device has a pair of edges of the piezoelectric substrate which define a predetermined distance therebetween. Then, the piezoelectric substrate is cut at at least one of a pair of positions which define a distance that is shorter than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be higher than the obtained frequency characteristic. The piezoelectric substrate is cut at at least one of a pair of positions which define a distance that is longer than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be lower than the obtained frequency characteristic.

Abstract: A longitudinally coupled resonator-type surface acoustic wave device includes interdigital transducers including a plurality of electrode fingers disposed along the propagation direction of a surface acoustic wave on a surface acoustic wave device. An electrically discontinuous portion is provided in a central portion, in the finger overlap direction, in adjacent electrode fingers in adjacent interdigital transducers, and at least one floating electrode is disposed in the finger overlap direction in the electrically discontinuous portion.

Abstract: A SAW apparatus includes a plurality of IDTs disposed on a piezoelectric substrate, and an edge-reflection-type SAW device in which surface acoustic waves are reflected by the edge surfaces of the piezoelectric substrate. The SAW device is housed in a package. On the top of a first main surface of the piezoelectric substrate, first and second pyroelectric charge cancellation electrodes are disposed in the vicinity of the edges defined by the main surface and the side surfaces. The first and second pyroelectric charge cancellation electrodes are electrically connected to the electrodes on the package which are electrically connected to each other within the package, respectively. Therefore, the adverse effects of pyroelectric charge which is generated due to a rapid change in temperature is minimized.

Abstract: A SAW apparatus includes a plurality of IDTs disposed on a piezoelectric substrate, and an edge-reflection-type SAW device in which surface acoustic waves are reflected by the edge surfaces of the piezoelectric substrate. The SAW device is housed in a package. On the top of a first main surface of the piezoelectric substrate, first and second pyroelectric charge cancellation electrodes are disposed in the vicinity of the edges defined by the main surface and the side surfaces. The first and second pyroelectric charge cancellation electrodes are electrically connected to the electrodes on the package which are electrically connected to each other within the package, respectively. Therefore, the adverse effects of pyroelectric charge which is generated due to a rapid change in temperature is minimized.

Abstract: An edge reflection type surface acoustic wave filter includes a piezoelectric substrate having two opposing edges and at least one interdigital transducer. The interdigital transducer includes split electrodes of paired electrode fingers arranged on the piezoelectric substrate such that a shear horizontal (SH-type) surface acoustic wave is excited on the piezoelectric substrate and is reflected between the two opposing edges. Each of the edges is preferably located at a distance of at least about &lgr;/2−5&lgr;/128 from a center of the paired equipotential electrode fingers, located at the respective outermost portions, in the surface acoustic wave propagation direction, of the interdigital transducer and less than about &lgr;/2 from the center of the paired equipotential electrode fingers, where &lgr; is a wavelength of the SH-type surface acoustic wave excited on the piezoelectric substrate.

Abstract: An edge-reflection surface acoustic wave filter includes IDTs disposed on a top surface of a piezoelectric substrate, and surface acoustic waves of the Shear Horizontal type are reflected between opposite edges. At least one outermost electrode finger in the direction of propagation of surface acoustic waves on the side of at least one of the edges is removed. Accordingly, desired filter characteristics can readily be achieved without causing variations in filter characteristics, spurious components at frequencies lower than the passband are minimized, and selectivity is greatly improved.

Abstract: A method for adjusting a frequency characteristic of an edge reflection type surface acoustic wave device includes the step of obtaining a frequency characteristic of an edge reflection type surface acoustic wave device having a piezoelectric substrate. The edge reflection type surface acoustic wave device has a pair of edges of the piezoelectric substrate which define a predetermined distance therebetween. Then, the piezoelectric substrate is cut at at least one of a pair of positions which define a distance that is shorter than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be higher than the obtained frequency characteristic. The piezoelectric substrate is cut at at least one of a pair of positions which define a distance that is longer than the predetermined distance when a final frequency characteristic of the edge reflection type surface acoustic wave device is to be lower than the obtained frequency characteristic.

Abstract: An edge reflection type surface acoustic wave device includes a surface acoustic wave substrate having an opposing pair of edges and at least one interdigital transducer located on the surface acoustic wave substrate. A Shear Horizontal type surface acoustic wave is generated by the interdigital transducer and reflected between the opposing pair of edges. The interdigital transducer is divided into a plurality of sub-IDT portions along a surface acoustic wave-propagating direction. Electrode fingers of the interdigital transducer which are closest to each other between adjacent sub-IDT portions are at the same potential so as not to be excited between the adjacent sub-IDT portions.

Abstract: A surface acoustic wave device is constructed to operate using an SH type surface acoustic wave and so that the surface acoustic wave is reflected by two opposite edges of the device. The surface acoustic wave device includes a piezoelectric substrate having first and second main surfaces and the two edges arranged opposite to each other and which connect the first and second main surfaces, respectively, and an interdigital transducer having a pair of interdigital electrodes provided on the first main surface of the piezoelectric substrate and arranged so that the electrode fingers thereof are interdigitated with each other. The electrode fingers of the interdigital electrodes include a plurality of split electrodes, except for the electrode fingers located at the outermost sides in the surface acoustic wave propagation direction. The electrode fingers on the outermost sides have a width that is different from that of the split electrodes.

Abstract: An edge reflection type surface acoustic wave filter includes a piezoelectric substrate having two opposing edges and at least one interdigital transducer. The interdigital transducer includes split electrodes of paired electrode fingers arranged on the piezoelectric substrate such that a shear horizontal (SH-type) surface acoustic wave is excited on the piezoelectric substrate and is reflected between the two opposing edges. Each of the edges is preferably located at a distance of at least about {fraction (&lgr;/2)}-{fraction (5&lgr;/128)} from a center of the paired equipotential electrode fingers, located at the respective outermost portions, in the surface acoustic wave propagation direction, of the interdigital transducer and less than about {fraction (&lgr;/2)} from the center of the paired equipotential electrode fingers, where &lgr; is a wavelength of the SH-type surface acoustic wave excited on the piezoelectric substrate.

Abstract: A surface acoustic wave filter includes edge-reflection type surface acoustic wave resonators arranged as series and parallel arm resonators and connected in a ladder configuration. The edge-reflection type surface acoustic wave resonators defining the series and parallel arm resonators are disposed on a single common substrate and arranged so as to be substantially parallel to the end surface of the edge-reflection type surface acoustic wave resonators.

Abstract: A surface acoustic wave device includes a surface acoustic wave substrate having first and second end surfaces, and a surface acoustic wave element provided on the surface acoustic wave substrate and operating using an SH-type surface acoustic wave. The surface acoustic wave element includes an interdigital transducer having a plurality of electrode fingers and a reflector having a plurality of electrode fingers. One of a pair of outermost electrode fingers is flush with one of the first and second end surfaces of the surface acoustic wave substrate, and the reflector is located at a side where the other of the pair of outermost electrode fingers is positioned, so that a SH-type surface acoustic wave excited by the IDT is confined between the reflector and the one of the first and second end surfaces.