Abstract: Disclosed is a surface acoustic wave transmission device comprising a piezoelectric substrate provided thereon with an input and output transducers for transmitting and receiving the surface acoustic wave, a package for accommodating the piezoelectric substrate, and an adhesion layer for fixing the bottom of the piezoelectric substrate to the ground plane of the package. The adhesion layer is made to have a thickness of .lambda..sub.R /2.6 or more wherein .lambda..sub.R : is the wave length of the surface acoustic wave at the main lobe of the operating frequency, so that unnecessary waves caused by bulk wave components are absorbed.

Abstract: Low reflectivity electrodes (2, 7) are provided on semiconductive and piezoelectric substrates (1, 6) including a layer (3, 9) of gold-germanium mixture and a layer (5, 8) of raw gold, or only a gold-germanium mixture (10), the total germanium content of the electrode comprising approximately 2%-3% of the total gold and germanium content of the electrode, and the thickness of the electrode being on the order of 1% of the acoustic wavelength.

Abstract: N.sup.2 acoustic wave devices (A,B,S,T; where N is an integer greater than unity) with substantially the same electrical impedance and transfer characteristics at a given operating frequency are electrically connected in a parallel-series arrangement which has substantially the same electrical impedance and transfer characteristics as any one of the individual N.sup.2 devices, but an increased active device area. The increased active area reduces stress and alleviates acoustically-induced migration in the metal of, for example, transducer electrode fingers (6,7) of resonators at high power levels. The parallel-series arrangement consists of N groups, each of which comprises N devices (A,B or S,T), the corresponding pairs of terminals (4,54 and 54,55) of which are connected in series.

Abstract: An acoustic surface-wave bandpass filter includes a substrate made of a piezoelectric material. Acoustic surface waves travelling on a substrate surface provided with electrically conductive narrow stripes, slits or grooves undergo interference, wherein acoustic surface waves excited at frequency in VHF and UHF range are taken out as electric signals. The number of interleaved fingers constituting input transducers and output transducers of the filter is selected greater for the transducer located at the center than those disposed at both end portions. Leakage of acoustic surface-wave energy from the end transducers can be remarkably reduced, while the number of the transducers constituting the filter can be decreased. Significant reduction of loss of the filter is thus attained.

Abstract: A surface wave device (10) having substrate with at least a surface layer of piezoelectric material (12) and at least one pair of opposing electrically conducting pads (14 and 16) is disclosed. A first group of at least three electrodes (18, 20 and 22) in a distance (24) of one half wavelength of a preselected operating frequency is disposed on the piezoelectric surface between the opposing pads. At least one of the electrodes is electrically connected to one of the opposing pads and the remaining electrodes are electrically connected to the other opposing pad. The sequence of the three electrodes is unevenly distributed with respect to which of the pads the electrodes are connected to. At least two additional groups of at least three electrodes similar to the first group have sequences of electrodes within each group that is distinct from the other groups.

Abstract: A surface wave device includes a substrate (12 in FIG. 7) having a surface layer of piezoelectric material (14), at least one pair of opposing electrically conducting pads (16 and 18) and at least two electrodes (20 and 22) which generate surface waves that vary significantly in strength in a direction transverse to the opposing pads. An ungrounded pad (16) forms an electrode array of parallel segmented electrodes (24), joined by electrically conducting connecting bars (26), having more segmented electrodes near the center of the transverse distance than near the pads. A grounded electrode (22) forms a segmented electrode array having segmented electrodes (44) joined by electrically conducting connecting bars (46) having fewer segmented electrodes near the center of the transverse distance than near the pads.

Abstract: A surface acoustic wave bandpass filter has a piezoelectric substrate for propagating a surface acoustic wave. An input transducer is formed on the substrate, with a pair of interdigital electrodes, for exciting a surface acoustic wave in response to an electrical signal. An output transducer is also formed on the substrate, with essentially the same structure for developing a filtered electrical signal from the surface acoustic wave propagated in the substrate. The input and output transducers are arranged so that the distance between them (L) satisfies the relationship: .lambda./2 n<L<.lambda./2 (n+1) (n is a positive integer), and .lambda./2 represents the distance between the centers of adjacent electrode fingers.

Abstract: A surface acoustic wave device includes a silicon substrate having a main surface with a given crystalline orientation, a zinc oxide layer deposited on the main surface of the silicon substrate and a dielectric layer as well as electrodes both formed in contact with said zinc oxide layer, so that a surface acoustic wave will be propagated along a given crystalline axis direction of the silicon substrate.

Abstract: Disclosed is an improved SAW monolithic convolver using dispersive interdigital transducers designed by a novel technique that allows systematic compensation of phase errors arising in other parts of the convolver. The invention involves a small change in the positional relationship among the electrodes in the input transducers. This change is calculated to be just sufficient to cause a phase error exactly equal to, but of opposite sign to, the aforementioned phase errors.

Abstract: A surface acoustic wave convolver comprises a piezoelectric substrate on which a plurality of conductive strip electrodes, an input signal transducer and a reference signal transducer are formed, and a semiconductive substrate on which depletion layer control electrodes and capacitance read-out electrodes are formed. The conductive strip electrodes are connected to the depletion layer control electrodes so that an output signal is taken up from the capacitance read-out electrodes.

Abstract: A piezoelectric device comprising a housing that contains a piezoelectric body bearing aluminum film electrodes. The exposed surfaces of the electrodes bear a passivating layer of amorphous aluminum oxide formed by heating the electrodes at a temperature between 250.degree. and 550.degree. C. in an atmosphere containing free oxygen.

Abstract: Disclosed is a surface acoustic wave interferometer, including a substrate on which are disposed a first reflector and a second reflector so as to define a multimode resonant cavity therebetween. A third reflector is positioned on the substrate so that a single mode resonant cavity is defined between the second and third reflectors. An input transducer generates surface acoustic waves in the single mode cavity, while an output transducer detects the interference between surface acoustic waves in the multimode and single mode cavities. A base is rigidly affixed to the substrate in the region of the single mode cavity so that a force applied to the substrate will alter the surface acoustic wave propagation characteristics within the multimode cavity.

Abstract: A withdrawal transducer structure is employed in a narrow-band surface acoustic wave device requiring many pairs of interdigital transducer fingers or in a high-frequency surface acoustic wave device in which the thickness of interdigital transducer fingers is large relative to the wavelength of the surface acoustic wave, so that the interdigital transducer fingers may not severely adversely affect the characteristics of the device. The interdigital transducer fingers in the input and output piezoelectric transducers are suitably partly omitted leaving some of them or dummy fingers are additionally provided to eliminate the adverse effect of the interdigital transducer fingers on the characteristics of the device, so that the narrow-band or high-frequency surface acoustic wave device can operate with improved performance without having any unnecessary frequency response.

Abstract: A surface acoustic wave device comprises a lower electrode provided on an elastic substrate, a piezoelectric film covering the lower electrode and an upper electrode provided on the piezoelectric film. The device is characterized in that the upper electrode comprises first and second double electrodes both opposed to the lower electrode.

Abstract: A surface acoustic wave (SAW) pressure sensor is mechanically supported within a vacuum sealing structure by a cylindrical metal sleeve which isolates the SAW sensor substrate from induced thermal strain resulting from temperature cycling of the structure, and which provides for a fluid conduit through the vacuum environment from the sensor diaphragm to an orifice formed through the wall of the structure.

Abstract: A surface acoustic wave record stylus is constructed from a support having a surface for propagating surface acoustic waves. A circular-shaped interdigital transducer launches the surface acoustic waves onto the support surface. The shape of the interdigital transducer is such that the surface acoustic waves are focused to a diamond stylus positioned at the center of the circular transducer.

Abstract: Passivated and low scatter acoustic wave devices comprise surface acoustic wave (SAW) and shallow bulk acoustic wave (SBAW) devices having transducers composed of oxidizable metal and layers of metal oxide on conventional acoustic wave substrates. Passivated transducers are achieved by forming a layer of oxide on an existing transducer. The method may be used to passivate a device packaged in a non-oxidizable package with oxidizable wire leads, thus combining complete protection with efficient manufacturing operations. Low scatter SAW transducers are achieved by forming the transducer and the interstitial insulating layer from a single layer of oxidizable metal by means of masking and oxidation operations.

Abstract: In devices comprising closely spaced metallized regions deposited upon a dielectric substrate, in particular acoustic wave devices, electric fields may arise between the regions due to pyroelectic effects or acquired static charges during production or subsequently. These fields can cause damage by arcing or cracking of the substrate. The present method overcomes this problem by providing resistive links between such regions so that the fields do not arise. Preferably the links are of metallizing formed simultaneously with the metallized regions. Application to a SAW convolver is described in which the links are strips of metallizing (7,8,9).

Abstract: A separate comb transducer is disclosed in a ZnO/Si SAW device to enable doubling of the possible operating frequency for a given photolithographic capability of the device. Frequency doubling is made possible by a single-phase structure having conductive and non-conductive surfaces equal to one-half of the SAW wavelength. By connection of two such structures in parallel, a balanced separate comb transducer is achieved for reducing signal levels due to direct coupling that otherwise occurs in the single-phase structure. Separate comb grating transducers are also disclosed to enable fabrication of higher frequency MZOS convolvers, with both the separate comb transducer and separate comb grating transducer being shown utilized in both the Rayleigh and Sezawa modes.

Abstract: A group-arranged type unidirectional surface acoustic wave transducer, which includes, in combination, groups of interdigital electrodes wherein the center-to-center distance between the electrodes is made equal to an integral number of wavelengths plus a quarter wavelength and further groups of interdigital electrodes wherein the center-to-center distance between the electrodes is made equal to an integral number of wavelengths plus three quarter wavelengths. According to the present invention, there is also provided a unidirectional surface acoustic wave device which can be employed as a filter by changing the frequency-amplitude characteristic of the surface acoustic wave.

Abstract: The use of fabricated periodic piezoelectric structures fabricated from h resistivity semiconducting crystals in detecting millimeter waves in the GHz range is disclosed.

Abstract: A surface acoustic wave device on a piezoelectric substrate comprises an interdigital transducer having an interdigital sending part in the forward direction and an interdigital reflecting part in the reverse direction. An electrical phase difference of .phi. (radian) is applied between the sending and reflecting parts, while the distance between the sending and reflecting parts providing a geometrical phase difference therebetween is established to be ##EQU1## where n is a positive integer and .lambda..sub.o is the wavelength of surface acoustic wave. A third, common electrode meanders between the sending and reflecting electrodes.

Abstract: A method is described for the fabrication of surface acoustic wave devices by the selective removal of one of the phases of a metallic eutectic solidified as a thin film having a lamellar morphology to form a first spaced array of metallic elements which then provides a self-aligned structure for the formation of a second array of metallic elements interdigitated with the elements of the first array.

Abstract: An acoustic surface wave transducer with a transmission interdigital electrode (2A) and a reception interdigital electrode (2B in FIG. 10A-D) on a piezoelectric surface (1) has been improved by reducing inband dispersion of frequency characteristics by providing an edge effect canceler (k.sub.1), which cancels an undesired surface wave (E-a, E-b) generated at the external edge of the extreme end finger of the interdigital electrodes. Said edge effect canceler is constructed so that the length of the extreme end finger (11a) of the interdigital electrode (10, 20 in FIG.5A) is half of the length of the second extreme end finger (12a) of said interdigital electrode, and the spacing between said extreme end finger and the second extreme end finger is 1/2 wavelength of the acoustic surface Wave.

Abstract: To enable increased power coupling into a SAW device for which voltage breakdown is a limiting factor in determining the maximum power which can be coupled, each transducer of the SAW device is replaced by a plurality of series-connected inter-digital transducers (IDTs). For operation in an Nth harmonic mode, there may be N series-connected IDTs which are offset from one another by 1/N wavelengths of the fundamental frequency for which the individual IDTs are designed; for high frequency SAW devices, this further increases the power which can be coupled into the device. The SAW device is particularly useful in a delay-line oscillator to constitute a microwave source for a local oscillator in a radio repeater.

Abstract: A surface acoustic wave device is provided with plural sets of input and output transducers arranged on a piezoelectric substrate with the input transducers and the output transducers being connected electrically in parallel, respectively. In order to minimize a loss which occurs due to the parallel connections of the input and output transducers, aperture dimensions of either the input transducers or the output transducers are selected such that static capacitances of the respective transducers are equal.

Abstract: An interdigital surface acoustic wave transducer comprises a substrate having at least two areas. One area has piezoelectric properties. Laid down on it is a main row with electrodes. The other area has no piezoelectric properties and carries an additional row with electrodes. Each row comprises two groups of electrodes arranged in parallel with one another. The electrodes of first groups of the rows are connected electrically to respective current-conducting pads. The electrodes of second groups of the rows are connected conductively to one another and are positioned between the electrodes of the first groups of the rows. As a result, overlap portions of the electrodes of the two groups are formed which have a constant length in the main row and a variable length in the additional row.

Abstract: In a preferred embodiment, a surface acoustic wave device comprises a piezoelectric substrate, a first electrode formed on the substrate and acting to convert an electrical signal into a surface acoustic wave, and second and third electrodes formed on the substrate and acting to convert the surface acoustic wave into an electrical signal. The second and third electrodes are disposed at different distances from the first electrode and connected electrically with each other. Electrode fingers of the second electrode are arranged in a relationship of the opposite polarity with respect to those of the third electrode so as to cause peaks in the constant frequency interval multi-peak frequency characteristics of the device acting as a filter to take place at frequencies which are (integer+1/2) times the constant frequency interval .DELTA.f. In another preferred embodiment, a plurality of surface acoustic wave device units are formed on a common piezoelectric substrate.

Abstract: A waveform recorder wherein surface acoustic waves excited in a piezoelecc-insulator-semiconductor layered structure produce a traveling electric field in the semiconductor substrate. Charges stored in the traveling potential wells and representing the instantaneous amplitude of a waveform to be recorded are transferred at high speed and density to different respective spatial locations. Because each successive well represents a different time instant of the waveform, the different spatial locations correspond to different times. The output signal from each of the locations can be selectively delayed before application to a display oscilloscope to enable display of the waveform at a rate many times slower than the actual frequency of the signal waveform.

Abstract: The invention relates to elastic surface wave pressure gauges.The gauge comprises a plate on which are located the electronic components of the gauge and a pressure sensor grouping the electromechanical elements on a header having connecting pins. The header is provided with a pressure inlet which traverses the plate.The invention is also applicable to the measurement of the pressures of fluids in order to optimize the supply to internal combustion engines. The pressure inlet is made of a rigid metal header and separately grounded for shielding of the surface acoustic wave electrodes to prevent "pull-in" where the oscillators inadvertantly lock on the same frequency.

Abstract: A structure for compressing an acoustic surface wave into a symmetric higher energy density output surface acoustic wave. Conductive strips are placed in parallel upon a piezoelectric surface. When a symmetric input is generated at one side of the multistrip coupler, the energy of the input wave is compressed into the center channel and is presented at the output in a single moded symmetric form.

Abstract: A surface-acoustic-wave device has a laminate formed of a semiconductor and a piezoelectric layer and a depletion layer control means locally provided at an interface portion of the semiconductor and said piezoelectric layer, wherein a parametric interaction is caused at a region other than an area where the depletion layer control means is provided and a depletion layer capacitance is controlled by applying a DC bias voltage and a pumping voltage to the depletion layer control means.

Abstract: A surface acoustic wave device includes a piezoelectric substrate, transmitting and receiving transducers provided on the surface of the substrate for propagating acoustic waves between the transducers, and absorbers provided between an end of the substrate and respective transducers for absorbing unwanted acoustic waves. The shape of the absorber is in relation to the energy distribution of the acoustic waves.

Abstract: An acoustic wave device wherein each electrode element of an interdigital transducer is buried or embedded between a pair of layers of piezoelectric material. The use of a multi-layer stack of layers of piezoelectric material enables each electrode element of the transducer to be sandwiched between a distinct pair of layers and thus to be insulated from the other electrode element or elements. Because of the insulation thus provided, the spacing between the fingers of each electrode element may be selected without fear of causing short circuits between electrode elements.

Abstract: An elastic surface wave device comprises an input transducer and an output transducer, these transducers being provided on one surface of a piezoelectric substrate and spaced apart a predetermined distance from each other. The input transducer is provided on its side facing the output transducer with at least one separate comb electrode which is electrically insulated from the rest of the input transducer.

Abstract: Temperature compensation is provided to a surface acoustic wave device including acoustoelectric transducers (12, 14) formed on a surface of a gallium arsenide substrate (10), by a composite layer including silicon dioxide (18, 26) and a mass loading metal (20, 24), which may be gold, titanium and gold, or other metals having Rayleigh wave velocities lower than that of gallium arsenide, such as silver and platinum.

Abstract: A surface wave component has a pair of interdigital transducer comb structures carried spaced apart on a surface of a substrate which is carried on a base plate. In one embodiment, signal leads extend beneath the substrate to areas adjacent the rear portions of the comb structures and are capacitively coupled thereto via the substrate which is a dielectric. In another embodiment, inductive coupling loops interconnect the rear portions of the comb structures of a respective transducer and another inductive loop is carried on the opposite side of the substrate for signal coupling. In both embodiments both symmetrical and asymmetrical signal coupling is provided by utilizing a grounding plate or layer as a signal lead.

Abstract: An elastic surface wave device having an input electrode, a pump electrode and an output electrode provided on a body of the device. The output electrode is juxtaposed with the input electrode on the body of the device on the same side with reference to the pump electrode and a multistrip coupler is provided between the pump electrode and the input and output electrodes so as to output, through the output electrode, a backward wave signal from the pump electrode.

Abstract: A wide band surface wave transducer is provided with means for launching a surface acoustic wave on a non-piezoelectric material by first launching the surface wave at the surface of a piezoelectric material spaced apart from the aligned non-piezoelectric element. A mechanical coupling array provides energy transfer between the two wave propagating surfaces.

Abstract: An acoustic surface wave device comprises transducers including interdigital electrodes formed on the surface of a piezoelectric material substrate of ceramic such as PZT, or a single crystal of such as LiNbO.sub.3 or a piezoelectric thin film of such as ZnO, wherein an electrical signal is converted into an acoustic surface wave and vice versa. The interdigital electrodes have been changed of the overlapping lengths of the adjacent electrode fingers that are overlapped with each other in accordance with a weighting function determined by a desired pass characteristic. A portion of the transducer region where an undesired acoustic surface wave is propagated, i.e. the portion outside of the envelope of the interdigital electrodes determined by the weighting function, is provided with an acoustic surface wave absorbing material such as silicon rubber. In a certain example, dummy electrodes may be provided between the electrode fingers of the interdigital electrodes.

Abstract: Apparatus for providing a plurality of filtered outputs is described incorporating a substrate suitable for propagating surface acoustic waves having an input transducer, a first plurality of spaced-apart taps coupled together, a second plurality of spaced-apart taps coupled together where at least two of the second plurality of taps are positioned in spaces between the first plurality of taps.The invention overcomes the problem of providing separate substrate surface area for each plurality of taps coupled together.

Abstract: An improved surface acoustic wave sensor in which two surface acoustic wave arrays are disposed in predetermined overlapping relationship by the use of a sealing compound which both establishes a thin sealed cavity and spaces the two surface acoustic wave arrays apart a predetermined distance, thereby eliminating the need for spacing rings or the like.

Abstract: An ultrasonic transducer including a thin piezo-electric substrate and an interdigital electrode radiating ultrasonic wave beams with excellent focusing characteristics into a liquid medium in contact with the substrate by applying AC voltages to the electrode.

Abstract: The device comprises a piezoelectric medium associated with a semiconducting and photosensitive medium on which the optical image is projected. Four transducers placed on the piezoelectric medium emit four elastic waves in two distinct directions with wave numbers such that the signal resulting from the interaction of these waves has a zero wave number. Depending on the waveform of the signals applied to the transducers, it is possible to obtain either point-by-point reading of the image or the Fourier transform of said image.

Abstract: An acoustic surface wave device including a three-phase unidirectional transducer. The transducer has three sets of interdigitated electrodes. The first and second sets of electrodes are each connected to bus bars, one on each side of the central axis of the transducer. The electrodes of the third set are connected to two bus bars one on each side of the central axis. The structure of the third set of electrodes and the bus bars connected thereto is symmetrical with respect to the central axis. The balanced structure of the transducer permits simplified impedance-matching and phase-shifting networks for enabling three-phase unidirectional operation of the transducer from a single phase electrical source.

Abstract: An acoustic wave resonator device comprises a substrate carrying a pair of spaced apart reflectors forming a resonant cavity that supports only three adjacent distinct resonant mode frequencies. An interdigital transducer is disposed on the substrate between the reflectors and includes an array of electrodes symmetrically arranged relative to a central point of the cavity to form a plurality of electrode pairs with the electrodes of each pair equally spaced on opposite sides of the central point. The central point of the cavity coincides with a node or an anti-node of the standing wave. If the two electrodes of each electrode pair are connected to the same terminal then the transducer has zero net coupling with one set of alternate modes of the cavity, whereas if said two electrodes are connected to opposite terminals then the transducer has zero net coupling with the other set of alternate modes.

Abstract: An acoustic surface wave filter element provided with two input and two output pins connected with the input and the output interdigital electrodes, respectively and an earth pin connected with a filter element shield casing is disposed on one surface of a circuit board, with the five pins extending through corresponding through holes in the circuit board to the other surface of the circuit board on which the pins are connected with corresponding conductive circuit patterns of the circuit board. The circuit patterns include a first signal pattern to be connected with one of the input pins, a first earth pattern connected with the other of the input pins, a second and a third signal pattern connected with one and another of the output pins, and a second earth pattern connected with the earth pin of the filter element.

Abstract: An elastic surface wave device includes a transducer having an elastic surface wave propagated in the direction of 75 to 133 degrees to a Y-axis on an X-cut lithium tantalate (LiTaO.sub.3) substrate.

Abstract: This invention provides an elastic surface wave device utilizing Bluestein-Gulyaev wave and constructed by a unitary body of a piezoelectric plate having a plurality of transducers thereon, wherein the wave propagation surface being coated with an insulating rubber and being embedded in molding by an insulating powdered epoxy resin, or whose body is attached on a unitary supporting substrate via double adhesive layers; wherein one layer is composed of one kind of adhesive resin and the other is composed of another kind of adhesive resin different from the former in ultrasonic property. This device is advantageous because it has a low spurious signal level without increasing insertion loss, and is easy to manufacture and inexpensive. This invention also provides an effective method for making the device.

Abstract: An acoustic surface wave device comprises a transducer including an interdigital electrode formed on the surface of a piezoelectric material substrate and cooperative with the same for converting an electrical signal into an acoustic surface wave and vice versa. The interdigital electrode comprises at least two divided comb shaped electrodes divided in the propagating direction of the acoustic surface wave and a common comb shaped electrode commonly coupled in an interdigital manner to the two divided comb shaped electrodes. Thus, the above described two comb shaped electrodes are disposed such that both divided electrodes arranged in succession in the propagating direction of the acoustic surface wave while the fingers of both divided electrodes extend in the same direction and the common comb shaped electrode is disposed such that the fingers of the common comb shaped electrode are interdigitated with the fingers of both divided comb shaped electrodes.