Abstract: A shear transverse wave device having transitions in the relaxation or tightening of wave trapping. Two embodiments are preferably utilized simultaneously. A first embodiment involves wave trapping fingers disposed within a propagation region between a transmitting and a receiving interdigital transducer. The wave trapping fingers provide a high width-to-spacing ratio of fingers proximate to the transducers and provide a lower ratio with approach to a center of the propagation region. The relaxed trapping reduces the adverse effects caused by surface perturbations, while the tight trapping at the transducers provides an efficient coupling of power to and from the device. The second embodiment is likewise concerned with decoupling of power. Absorptive film is placed at the opposed edges of the device to suppress spurious reflections from the edges.

Abstract: An SAW (surface acoustic wave) device is disclosed, in which a plurality of SAW delay lines and a plurality of SAW convolver elements are combined; signals delayed by predetermined amounts by the combined SAW delay lines are used as input signals to the SAW convolver elements; and output signals thus obtained from the plurality of SAW convolver elements are added together to be taken out so that apparently a processing time, which is equal to a signal processing time of a single SAW convolver element multiplied by an integer, can be obtained.

Abstract: A fluid sensing device such as a Shear Transverse Wave device or a Love Wave device having a wave-trapping structure that provides tight surface trapping at transduction and sensing regions, but permitting a deeper penetration of wave energy at the interface of a seal with the wave-trapping structure. In the STW device, wave-trapping fingers are selectively varied in thickness, width or both to achieve the selective trapping. In an LW device, a wave-trapping plate is reduced in thickness at seal regions.

Abstract: A novel surface acoustic wave (SAW) element for use in a stabilized oscillator circuit capable of coupling directly to external circuitry includes a pair of opposed transducers formed on a surface of a piezoelectric crystal for launching surface acoustic waves into a resonant cavity formed by opposed reflectors on the crystal surface. The element is characterized by a supplemental transducer coupled to the cavity for directly providing external circuitry with signals corresponding to the resonant surface acoustic waves.

Abstract: An acoustic wave device comprises an acoustic wave transducer coupled to an acoustic wave propagating substrate. The acoustic wave transducer converts signal energy between electrical and acoustical forms. Acoustic reflectors are placed one on either side of the acoustic wave transducer. The acoustic reflectors are composed of acoustic reflection elements spaced approximately one wavelength apart, and provide enhanced acoustic acoustic reflections together with relaxed fabrication constraints.

Abstract: A surface acoustic wave resonator having an interdigital transducer on a piezoelectric substrate. Grating reflectors, which have electrode strips of the same width and the same pitch as those of electrodes of the interdigital transducer and of a number smaller than 1/5 that of said electrodes of said interdigital transducer, are disposed at the intervals equal to said pitch at both sides of said interdigital transducer on a surface wave propagation path. The electrode portion of the interdigital transducer is weighted so that the aperture of the interdigital transducer is maximum at the center of the interdigital transducer and uniformly decreases toward its both sides along respective sides of a rhombus with its vertices at the centers of the outermost electrode strips of the grating reflectors.

Abstract: A surface acoustic wave device comprises a piezoelectric substrate, a plurality of input transducers, formed on the substrate, for generating surface acoustic waves corresponding to input signals, a plurality of waveguides which are juxtaposed on a region of said substrate where the surface acoustic waves generated by said input transducers overlap each other, and in which signals are generated due to an interaction of the surface acoustic waves, the waveguides generating surface acoustic waves corresponding to the signals due to the interaction, and an output transducer for receiving the surface acoustic waves generated from the waveguides, converting the signals due to the interaction into electrical signals, and extracting the electrical signals, the output transducer being constituted by a plurality of portions, juxtaposed in a widthwise direction of the surface acoustic waves generated from the waveguides, for receiving some components of the surface acoustic waves generated from the waveguides, and outp

Abstract: In a surface acoustic wave device for removing narrow band signals, detection sensitivity is significantly improved by disposing a group of metal strip arrays on the side opposite to output transducers with respect to input transducers on the surface of a piezo-electric film and connecting a group of diode arrays with this group of metal strip arrays.

Abstract: A surface acoustic wave device includes a substrate having a surface which supports surface acoustic wave propagation and having a pair of interdigitated transducers disposed thereon. Each of the pair of interdigitated transducers has a set conductive members. To improve the ratio of devices having acceptable long-term frequency stability characteristics to those without such acceptable characteristics, the conductive members of the pair of interdigitated transducers have a larger than conventional thickness.

Abstract: An SW resonator has a substrate of piezoelectric material. Two reflectors are applied onto the one substrate side. Input and output transducers are situated between the reflectors. The SW resonator is expanded to form an SW resonator having three electrical gates by arranging an additional transducer between the reflectors.

Abstract: An SAW convolver is disclosed, in which a pair of input transducer means disposed at the left and right end portions on a piezoelectric substrate having a velocity dispersion consists of a plurality of pairs of input transducers and the distance between different pairs of input transducers differs from each other so as to compensate the velocity dispersion.

Abstract: A surface acoustic wave device comprises a substrate, a plurality of input transducers formed on the substrate for generating first and second surface acoustic waves propagating in opposite directions to each other, and a plurality of waveguides arranged in a direction orthogonal to the propagating direction of the first and second surface acoustic waves on a region where the first and second surface acoustic waves overlap. Each waveguide producing a third surface acoustic wave propagating in a direction where the waveguides are arranged, with the interaction between the first and second surface acoustic waves, and on at least two of the waveguides, third surface acoustic waves reflected at respective side edges cancel each other, and an output transducer converts the third surface acoustic waves propagating from the waveguides into an electrical signal.

Abstract: A SAW device comprises a substrate, input and output interdigital electrodes provided on the substrate alternately to form a row of electrodes, and a pair of open strip reflectors disposed at both ends of the row, the input interdigital electrodes having a first pair number representing the number of pairs of opposing finger electrodes forming the input electrode, the output interdigital electrodes having a second pair number representing the number of pairs of opposing finger electrodes forming the output electrode, wherein the first pair number and second pair number are set different in the adjacent input and output electrodes with a predetermined ratio therebetween, the first pair number is changed in each input electrodes in the row, and the second pair number is changed in each output electrodes in the row.

Abstract: A surface acoustic wave apparatus wherein a reflector for reflecting a surface acoustic wave is provided on both sides of at least one of an input interdigital transducer and an output interdigital transducer, or, on one side of one of the input interdigital transducer and the output interdigital transducer.

Abstract: A multiple-reflection, long-path wave transmission device is fabricated from a single crystal silicon plate by micromachining straight walled rectangular cavities into the plate to reflect ultrasonic waves along an extended transmission path defined by the rectangular cavities. An input transducer is coupled to the silicon plate to introduce ultrasonic waves into the plate in response to an input signal. The ultrasonic waves travel in the silicon plate along the transmission path defined by the straight walled reflective cavities. An output transducer is similarly coupled to the silicon plate to receive the ultrasonic waves at the completion of the transmission path and to generate an output signal representative thereof. Additional sloped wall cavities are formed in the silicon plate to border the extended transmission path. The sloped wall cavities prevent cross coupling of waves traveling in different portions of the path and absorb energy traveling in undesired directions and modes.

Abstract: An elastic surface wave convolve comprises a piezoelectric substrate, a plurality of input transducers formed on said substrate for generating elastic surface waves corresponding to respective input signals, a plurality of waveguides provided side by side on a region of the substrate where elastic surface waves radiated from the input transducers overlap, wherein a convolution signal of input signals is produced due to parametric mixing effect of elastic surface waves in respective waveguides, these waveguides generating an elastic surface wave corresponding to the convolution signal, and an output transducer for receiving the elastic surface wave radiated from the waveguides and taking out an electrical signal by conversion of the convolution signal, wherein the width of elastic surface wave radiated from the waveguides is narrower immediately before reception with the output transducer than immediately after radiation from the waveguides.

Abstract: Interdigital transducers (3, 4) and reflectors (5, 6) are formed on a piezoelectric substrate (2) by an aluminum film. The aluminum film is crystallographically oriented in a constant direction, whereby stressmigration of the aluminum film is suppressed.

Abstract: An acoustic transducer for an acoustic wave device which includes an acoustic wave propagating substrate, the transducer adapted to couple to an electrical load and/or source. The transducer includes at least a pair of comb electrodes formed on the substrate. It includes apparatus for applying an electrical load and/or source across the pair of comb electrodes. The first of the combs has a plurality of electrode fingers. The second comb has at least one electrode finger. The widths of the electrode fingers are the same. Gaps of at least two different widths are disposed between the electrodes.

Abstract: An ACT (acoustic charge transport) filter comprises a plurality of SAW (surface acoustic wave) transducers and an interleaved filter bank coupled on either transversal side of the SAW transducer. Each interleaved filter bank comprises two filters, and the electrodes of the two filters are interleaved. Isolation between the interleaved electrodes is supplied by a meadering ground. The electrodes are apodized to facilitate weighted sampling of the delayed signal. Multiple frequency characteristics may be extracted from a single ACT filter by cascading the SAW transducer/interleaved filter bank combinations. Weighted sampling of the delayed signal may also be accomplished through weighted withdrawal of the ACT filter.

Abstract: A delay device comprises a semi-conductor chip having acoustic charge transport channel disposed therein; a contact operably connected to and disposed at one end of the channel for injecting an electronic signal into the channel; a transducer for generating a single frequency, large amplitude acoustic surface wave through the channel for thereby transporting the electronic signal through the channel; a plurality of electrodes operably associated with the channel and disposed along the propagation path of the surface acoustic wave for non-destructively sensing the electronic signal; switches monolithically disposed on the chip and operably connected to the electrodes for preselecting any one of the electrodes, thereby extracting a delayed replica of the signal from the channel; and an output circuit for processing the extracted signal for generating an output.

Abstract: A SAW device having a piezoelectric substrate and interleaved metal electrodes formed on the substrate, in which the formation of the electrodes on the substrate is carried out by sputtering. Further, the metal electrodes may contain an additive of Cu, Ti, Zn, Mg, Fe, Ni, Cr, Ga, Ge, Sn, Pd or Ta. The resulting SAW device is capable of dealing with high frequency electric signals of a larger amplitude, or higher power electric signals, as compared with the conventional SAW device.

Abstract: A surface acoustic electric wave device of the type comprising, over a large face of a planar piezo-electric substrate, a first row of parallel conductive fingers having an individual geometry chosen and distributed according to a chosen distribution arrangement along this row, a second row of parallel conductive fingers having an individual geometry chosen and distributed according to a chosen distribution arrangement along this row, the second row being interspaced from the first so as to allow a propagation of surface acoustic waves between the fingers of the first row and those of the second, which imparts to the device spectral and/or temporal characteristics defined by the acoustic propagation and the frequency selectivity due to the geometry of the fingers.

Abstract: Amplitude error compensation is provided for a surface acoustic wave (SAW) reflective array correlator (RAC) device having a first reflective array grating fed by an input interdigital transducer and a second reflective array grating which feeds the reflected SAW signal output from the first array grating to an output interdigital transducer. A third or auxiliary reflective array grating is disposed between the first and second array gratings to reflect a portion of the SAW signals reflected from the first array grating to the second array grating to an acoustic absorber. The portion of the SAW signals reflected to the acoustic absorber are those SAW signals which when present in the output of the second array grating which is fed to the output transducer produce the unwanted amplitude errors. The third reflective array grating is fabricated of a photosensitive polymer material so that the frequency and amplitude selective configuration of the grating may be obtained by using photolithographic techniques.

Abstract: An amplitude error compensated surface acoustic wave reflective array corator is provided having an input interdigital transducer feeding a first slanted reflective array grating, a second slanted reflective array grating feeding an output transducer and a third, amplitude error compensation slanted reflective array grating feeding the output transducer. The third array grating receives only the leakage surface acoustic waves leaking past the second array grating from the first array grating and has a frequency and amplitude selective configuration which enables it to select those leakage surface acoustic wave signals which when added to the output of the second array grating by means of a multistrip coupler and fed to the output transducer provide an amplitude error compensated output RF signal.

Abstract: An acoustic charge transport device having a number of signal tap electrodes has revealed unexpected insensitivity to electrode spacing and unexpected sensitivity to electrode width. Spacing of one-half SAW wavelength between consecutive electrodes and an electrode width of .lambda./20 are preferred for low frequency response.

Abstract: A surface device with a conversion structure (12) mounted on the substrate (2) but outside the surface of the substrate provided for surface wave propagation. The conversion structure eliminates undesirable surfaces which occur.

Abstract: Disclosed is a surface-acoustic-wave convolver having a toroidal coil connected to each interdigital electrode as a matching and balanced-to-unbalanced converting circuit. The use of the toroidal coil wound on an associated toroidal core permits the reduction of required parts in number thanks to its dual function, and accordingly reduction of manufacturing cost and size of the device. Still advantageously the use of such a toroidal winding permits the suppression of spurious or noise signals in an SAW device.

Abstract: Amplitude error compensation is provided for a surface acoustic wave (SAW) lanted array correlator (SAC) device having an input interdigital dispersive slanted array transducer feeding a plurality of frequency dispersed SAW signals to an output interdigital dispersive slanted array transducer over a plurality of parallel, frequency dispersed first paths. A reflective array grating having a frequency and amplitude selective configuration is disposed between the input and the output transducers to reflect along a second path to an acoustic absorber a portion of the SAW signals sent from the input transducer to the output transducer. The second path is perpendicular to and traverses the plurality or first paths. The portion of the SAW signals reflected to the acoustic absorber are those SAW signals which when present in the output of the output transducer produce the unwanted amplitude errors.

Abstract: A surface acoustic wave device employs in-line input and output transducers disposed on a piezoelectrically active surface. Two U-configured multi-strip couplers are disposed between the input and output transducers in an overlapped, opposing configuration in order to convolve the side lobe energy from the input transducer across substantially all of the aperture of the output transducer.

Abstract: A method of adjusting the center frequency of a SAW device by providing a substrate capable of propagating a surface acoustic wave thereon having input transducer electrode on one end portion thereof, output transducer electrodes on the opposite end portion thereof and a waveguide portion therebetween, applying an RF input signal to the input transducer and providing an indication of the output obtained from the output transducer and etching the entire device with an etchant until the indication has reached a predetermined status.

Abstract: An SAW convolver having a piezoelectric film / insulating layer / low impurity concentration Si epitaxial layer / high impurity concentration Si epitaxial layer structure is disclosed, in which the low impurity concentration Si epitaxial layer is replaced by a GaAs epitaxial layer. In this way, it is possible to improve concentration characteristics with respect to those obtained by the prior art structure described above and it is unnecessary to control the thickness of the epitaxial layer so strictly as for the prior art structure.

Abstract: A surface acoustic wave (SAW) waveguide-coupled resonator filter is overcoupled to produce an essentially constant conductance and susceptance over at least the bandwidth of a desired notch filter. The SAW resonator filter is embedded in a bridged-T allpass circuit to provide the pair of equal capacitances of the circuit, and the resonator ground is connected to one terminal of the parallel inductor of the circuit having the other terminal connected to a system ground.

Abstract: A piezoelectric semiconductor device for greatly increasing the linear channel length and storage capacity of an acoustic charge transport (ACT) device. Synchronized surface acoustic wave devices are aligned approximately orthogonally to each other so that in an angular portion of the channel, the charge packets of an input signal are bent at approximately a 45.degree. angle. As a result, channel length and therefore storage capacity of the channel and ACT device are greatly increased. One embodiment is a 45.degree. angle spiral channel. Another embodiment is a serpentine channel with 45.degree. angle bends.

Abstract: A surface acoustic wave device comprises a piezoelectric substrate and a plurality of electrode fingers which are located on the piezoelectric substrate along the progagation direction of a surface acoustic wave. The electrode fingers are located on the piezoelectric substrate at a pitch of about 1.5.lambda.o/2 (where a symbol .lambda.o indicates a wavelength of a surface acoustic wave with a frequency equivalent to the center frequency of the surface acoustic wave device). The width of each of the electrode fingers is about 1.5.lambda.o/4. The electrode fingers are located on the substrate so as to be electrically independent of an external circuit and each other.Since the width of electrode fingers is about 1.5.lambda.o/4, the surface acoustic wave device can be produced without fine processing techniques.

Abstract: An electrode structure for use with a surface acoustic wave device which has the same velocity as the transducers and the gratings forming the device but no reflections and which can be used to vary structure reflectivity.

Abstract: An electrode structure for use with a surface acoustic wave resonator which has the same velocity as the transducers and gratings but no reflections; a second embodiment provides an electrode structure having a velocity equal to the velocity of the transducers and gratings but that has a coefficient of reflectivity that can be predetermined by varying the width of the electrodes in the electrode structure.

Abstract: A surface-acoustic-wave (SAW) H.sub.2 O phase-change sensor capable of distinguishing air, water, dew, frost and ice. The sensor can also distinguish various frost thicknesses. The sensor has a size allowing batch fabrication of the chips, and allowing the device to fit in small spaces such as between fins of an evaporator. The sensor is fabricated on a strong piezoelectric substrate with a short acoustic path length. The SAW phase-change sensor experiences large changes in insertion loss and impedance upon deposition of water in various phases. The sensor has a hydrophobic surface treatment covering the SAW sensor surface, and if placed in a vertical position will self-clean during a refrigeration defrost cycle.

Abstract: A surface acoustic wave device including a surface acoustic wave convolver element, provided with two input transducers disposed on a piezoelectric substrate and a rectangular output gate disposed between the two input transducers, is disclosed, in which it comprises further a binary tree connected with the output gate and a matching circuit connected with the binary tree stated above, which is a Tchebycheff type impedance transforming circuit.

Abstract: In an SAW convolver composed of a substrate having a multi-layered structure comprising at least a piezoelectric film, self convolution is suppressed by disposing a first and a second array electrode disposed between the gate electrode and a pair of input electrodes, respectively, each of which consists of a high impurity concentration semiconductor layer. Further a convolution integrator is constituted by using such a convolver.

Abstract: A surface acoustic wave device having interdigitated transducers comprised of an improved metalization system including copper and titanium doped aluminum transducers. A method of producing the interdigitated transducers includes deposition of the metals on a quartz substrate and subsequent heat treatment. The metalization system provides SAW devices having improved long-term frequency stability, particularly when operated at high power levels. The surface acoustic wave device may be incorporated in a feedback loop of an amplifier to form an oscillator circuit.

Abstract: A strip coupled type convolver includes an aluminum nitride (AlN) layer and a semiconductor layer both provided on a single sapphire substrate, and includes many metal strips extending across a surface wave propagating path on a surface of the AlN piezoelectric layer to transmit a potential on the piezoelectric surface to a Schottky diode array provided on the semiconductor surface to cause a nonlinear interaction.

Abstract: The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle. Problems of crosstalk and wave reflection may produce spurious code pulses in systems of this type. The invention provides techniques for eliminating or reducing these unwanted pulses.

Abstract: A SAW resonator includes resonating SAW transducer units formed on a piezoelectric substrate and juxtaposed in a direction of propagation of acoustic waves, and a unidirectionally reflecting SAW transducer unit provided in each end of the juxtaposed resonating SAW transducer units on the substrate. Each resonating SAW transducer unit includes first and second SAW transducers connected in series and/or in parallel with each other.

Abstract: Techniques for adjusting the surface acoustic wave velocity of a packaged SAW device are described. A first technique involves depositing a film from a cover of the device onto a surface wave propagating surface thereby providing a localized region on said surface where the acoustic properties and, hence, the velocity characteristics of the surface wave propagating surface are altered. An alternate embodiment of a pair of beams are directed through a transparent cover and converge on the surface wave propagating surface, selectively removing a portion of said surface to provide a localized alteration in the acoustic properties of the surface wave propagating surface.

Abstract: A surface acoustic wave convolver comprises a piezoelectric substrate, a plurality of input transducers formed on the substrate and adapted to respectively generate surface acoustic waves in response to input signals, and a plurality of wave guide paths parallelly provided on the substrate in a superposing area of the surface acoustic wave generated by the input transducers to each generate a convolution signal of the input signals by non-linear interaction of the surface acoustic waves therein. The convolution signals generated in neighboring wave guide paths are mutually different by 180.degree. in phase, and the wave guide paths are adapted to generate surface acoustic waves corresponding to the convolution signals and an output transducer receives the surface acoustic waves generated by the wave guide paths and converts the convolution signals into an output electrical signal.

Abstract: An apparatus is featured for controlling remote devices. The status or one or more switches associated with remote devices may be transmitted along a single transmission line. One end of the transmission line contains a surface acoustical wave (SAW) delay line. The SAW delay line responds to an interrogation pulse of radio frequency electromagnetic energy with a series of delayed pulses, each of which transmits the status of a switch by means of the presence or absence of the pulse. The SAW delay line and switches are completely passive, requiring no power source. The transmission line may optionally be interrupted and coupled by means of a pair of inductive coils. This offers the potential for rotation, as within a steering column of an automobile, without wear or damage to the transmission line. The other end of the transmission line contains electronic circuitry to provide the interrogation pulse, to decode the return delayed pulses, and to drive other circuitry as required by the switch positions.

Abstract: A separated substrate acoustic charge transport device includes a surface acoustic wave (SAW) element fabricated on a piezoelectric substrate and an acoustic charge transport element fabricated on a separate semiconducting substrate. The substrates are separated by a small gap such that the evanescent electric field associated with the propagating SAW wave extends into a transport channel in the acoustic charge transport element to provide for longitudinal charge confinement and transport along the transport channel.

Abstract: A novel heterostructure acoustic charge transport (HACT) device is capable of direct optical modulation. The device includes a transducer fabricated on a substrate structure that launches surface acoustic waves. A reflector is formed in the substrate structure at an end portion adjacent to the transducer for reflecting the surface acoustic waves. Also included is an electrode configured with the transport channel at an end thereof distal to the transducer for generating electrical signal equivalents of the propagating electrode charge. The device is characterized by a transport channel with an intrinsic vertical electrical potential such that electron-hole pairs created by incident electromagnetic radiation are separated from one another before recombination, with electrical charges therefrom provided to the surface acoustic waves.

Abstract: An acoustic surface wave element having an oscillation frequency stable against temperature changes, and a wide range of oscillation frequency adjustment, is provided by an acoustic surface wave element comprising: a substrate of a 36.degree. rotated Y-cut single crystal lithium tantalate having X, Y and Z crystal axes and a top surface and side walls; electrodes formed on the top surface of the substrate such that an acoustic surface wave is propagated in a direction of the X-axis of the substrate and an oscillation of the acoustic surface wave occurs at a predetermined frequency, the electrodes having a thickness equal to 1 to 4% of a wavelength of the acoustic surface wave at the oscillation; and a plasma CVD-deposited layer of silicon dioxide covering the electrodes and the substrate, the silicon dioxide layer having a refractive index of 1.445 to 1.486 and a thickness equal to 16 to 26% of the wavelength of the acoustic surface wave at the oscillation.

Abstract: A high frequency narrow-band pass multi-mode filter in constructed in such manner that SAW of SSBW resonators are closely disposed to each other on a single piezoelectric substrate to generate different vibration modes of different resonance frequencies, conditions that the resonators are acoustically coupled to each other to cause these vibration modes, are experimentally found, and the above conditions are satisfied by the filter.In order to reduce the ohmic loss of a very narrow common bus bar, the number of strip pairs of electrode in both interdigital transducers (hereinafter referred to as IDT) is minimized and instead reflectors are provided on the both sides TDTs to compensate for the reduction of its Q value. A part of the bus bar for the IDT electrodes is formed integral with some or all of gratings of the reflectors, whereby the connecting positions of the grating electrodes with respect to lead terminals can be positioned with a high freedom.