Abstract: A surface acoustic wave filter includes a piezoelectric substrate and a plurality of surface acoustic wave resonators mounted on the piezoelectric substrate. The plurality of surface acoustic wave resonators are connected so as to constitute a lattice-type circuit having series-arm resonators and lattice-arm resonators, and a capacitance ratio &ggr; value of the lattice-arm resonators and a capacitance ratio &ggr; value of the series-arm resonators are made different from each other.

Abstract: A surface acoustic wave filter device, comprising a surface acoustic wave filter element having a ladder type circuit electrically connected and mechanically fixed to a package by a face down work method, wherein a micro strip line connected to a series arm resonator and/or a parallel arm resonator is provided inside the package, whereby excellent filter characteristics can be provided by the addition of the inductance component thereof.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate and a plurality of surface acoustic wave resonators provided on the piezoelectric substrate and connected to define a ladder filter circuit.

Abstract: One form of evaluation apparatus comprising a plurality of light sources vertically arranged by one side of a carrier line in width direction Y perpendicular to carrying direction X of the carrier line; and a light-receiving section arranged by an opposite side of the carrier line in the width direction Y perpendicular to the carrying direction X of the carrier line.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate, and at least two series arm resonators and at least one parallel arm resonator each constituted by a one-port surface acoustic wave resonator, disposed on the piezoelectric substrate. The at least two series arm resonators and at least one parallel arm resonator are connected to define a ladder-type circuit. Each of the at least two series arm resonators includes an interdigital transducer weighted by apodization, and the apodizations for the at least two series arm resonators are different from each other.

Abstract: A surface acoustic wave filter has a plurality of interdigital transducers arranged in a ladder circuit structure. Each of the interdigital transducers has a first comb-shaped electrode and a second comb-shaped electrode, each of which has a plurality of electrode fingers and a bus bar connected to first ends of the plurality of electrode fingers. The first and second comb-shaped electrodes interdigitate with each other so that second ends of the plurality of electrode fingers of the first comb-shaped electrode extend toward the bus bar of the second comb-shaped electrode. A gap is created in at least one of the interdigital transducers to cause a ripple in the pass band of the surface acoustic wave filter such that the ripple increases the steepness of the filter characteristics at the high frequency shoulder of the pass band. The gap is defined between the bus bar of the first comb-shaped electrode and the second ends of the plurality of electrode fingers of the second comb-shaped electrode.

Abstract: A branching filter is a surface acoustic wave device in which a first filter having a relatively low bandpass frequency and a second filter having a relatively high bandpass frequency are connected to a common terminal. A junction-side resonator that is included in the second filter and that is connected in closest proximity to the common terminal is connected in series. The resonant frequency fsr of the junction-side resonator is higher than the center frequency f0, which is the center of the passband, of the second filter, and is more preferably set so as to satisfy the expression: f0+BW×0.2≦fsr≦f0+BW×0.7, where BW is the bandwidth of the passband.

Abstract: A surface acoustic wave apparatus includes a first filter and a second filter, which are integrated into one package, and, filter signal terminals of the first and second filters are connected to package signal terminals of the package through different paths which are insulated from each other. A signal line extended from filter signal terminals is connected to one common terminal outside the package. The signal line and the common terminal define a coupling section. An inductance device is connected in parallel to the coupling section as a matching circuit.

Abstract: A ladder circuit type SAW filter device includes series arm resonators and parallel arm resonators that are defined by SAW resonators. Among the parallel arm resonators, a first parallel arm resonator that is connected to one of an input end and an output end and a second parallel arm resonator that is connected to a junction between two series arm resonators have the relationship of Cp1×2<Cp2, where Cp1 represents the capacitance of the first parallel arm resonator and Cp2 represents the capacitance of the second parallel arm resonator. The inductance of an inductor that is connected to the second parallel arm resonator is equal to or less than the inductance of the inductor that is connected to the first parallel arm resonator. The SAW filter device has superior steepness of filter characteristics in the lower range of a pass band and outstanding attenuation in a stop band.

Abstract: A surface acoustic wave device includes a piezoelectric substrate made of LiTaO3 and at least one interdigital transducer provided on the substrate and having a plurality of electrode fingers. The polarization direction in at least one gap portion between electrode fingers of the at least one interdigital transducer is different from the polarization direction in other gap portions between electrode fingers on the same propagation path.

Abstract: An extremely convenient apparatus for evaluating the inner quality of vegetables and fruits which is small and inexpensive, can be introduced easily even by small-scaled enterprisers, in which an installation place can be changed easily, and safety and promptness of the replacing work of light sources are fully taking into consideration is provided.

Abstract: A surface acoustic wave filter includes a Y-cut X-propagation LiTaO3 substrate having a cut angle of about 38 degrees to about 46 degrees, at least first and second series arm surface acoustic wave resonators connected in series to define a series arm, and at least one parallel arm surface acoustic wave resonator connected to the series arm. Each of the first and second series arm surface acoustic wave resonators includes an interdigital transducer having a plurality of pairs of electrode fingers, and where a number of pairs of the electrode fingers of the first series arm surface acoustic wave resonator is represented by N (N=natural number), the corresponding number of the second series arm surface acoustic wave resonator differs from n=N (n=natural number).

Abstract: A surface acoustic wave device is arranged such that surface acoustic wave energy is trapped substantially perpendicularly to the surface acoustic wave propagation direction. At least one interdigital transducer having a plurality of electrode fingers and first and second bus bar electrodes is located on a piezoelectric substrate on which a surface acoustic wave is excited, and has an anisotropy index &ggr; of less than about −1 in the propagation direction. The electrode fingers each have a film thickness of not less than about 0.04 &lgr; in which &lgr; is the wavelength of the surface acoustic wave. At least a portion of the first and second bus bar electrodes have a thickness that is larger than that of each electrode finger.

Abstract: A surface acoustic wave device is arranged such that surface acoustic wave energy is trapped substantially perpendicularly to the surface acoustic wave propagation direction. At least one interdigital transducer having a plurality of electrode fingers and first and second bus bar electrodes is located on a piezoelectric substrate on which a surface acoustic wave is excited, and has an anisotropy index &ggr; of less than about −1 in the propagation direction. The electrode fingers each have a film thickness of not less than about 0.04&lgr; in which &lgr; is the wavelength of the surface acoustic wave. At least a portion of the first and second bus bar electrodes have a thickness that is larger than that of each electrode finger.

Abstract: A surface acoustic wave filter includes at least two series arm surface acoustic wave resonators provided in an series arm and at least one parallel arm surface acoustic wave resonator provided in a parallel arm. At least one of the series arm surface acoustic wave resonators has a plurality of anti-resonant points and a sub-resonant point located between the anti-resonant points. The sub-resonant point substantially matches an anti-resonant point of at least one of the remaining series arm surface acoustic wave resonators.

Abstract: A surface acoustic wave filter has a plurality of interdigital transducers arranged in a ladder circuit structure and includes a series arm and at least two parallel arms. Each of the interdigital transducers has a first comb-shaped electrode and a second comb-shaped electrode, each of which has a plurality of electrode fingers and a bus bar connected to first ends of the plurality of electrode fingers. The first and second comb-shaped electrodes interdigitate with each other so that second ends of the plurality of electrode fingers of the first comb-shaped electrode extend toward the bus bar of the second comb-shaped electrode. A gap is created in the interdigital transducers defining the surface acoustic wave resonators that are connected to the parallel arms to cause ripples to be distributed in the pass band of the surface acoustic wave filter such that the ripples improve the flatness of the pass band.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate and a plurality of surface acoustic wave resonators provided on the piezoelectric substrate and connected to define a ladder filter circuit.

Abstract: A surface acoustic wave filter has a plurality of interdigital transducers arranged in a ladder circuit structure. Each of the interdigital transducers has a first comb-shaped electrode and a second comb-shaped electrode, each of which has a plurality of electrode fingers and a bus bar connected to first ends of the plurality of electrode fingers. The first and second comb-shaped electrodes interdigitate with each other so that second ends of the plurality of electrode fingers of the first comb-shaped electrode extend toward the bus bar of the second comb-shaped electrode. A gap is created in at least one of the interdigital transducers to cause a ripple in the pass band of the surface acoustic wave filter such that the ripple increases the steepness of the filter characteristics at the high frequency shoulder of the pass band. The gap is defined between the bus bar of the first comb-shaped electrode and the second ends of the plurality of electrode fingers of the second comb-shaped electrode.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate and a plurality of surface acoustic wave resonators mounted on the piezoelectric substrate. The plurality of surface acoustic wave resonators are connected so as to constitute a lattice-type circuit having series-arm resonators and lattice-arm resonators, and a &ggr; value of the lattice-arm resonators and a &ggr; value of the series-arm resonators are made different from each other.

Abstract: A surface acoustic wave filter includes a piezoelectric substrate, and at least two series arm resonators and at least one parallel arm resonator each constituted by a one-port surface acoustic wave resonator, disposed on the piezoelectric substrate. The at least two series arm resonators and at least one parallel arm resonator are connected to define a ladder-type circuit. Each of the at least two series arm resonators includes an interdigital transducer weighted by apodization, and the apodizations for the at least two series arm resonators are different from each other.