Abstract: A surface wave filter with a wafer-shaped substrate formed of monocrystalline piezoelectric material having a surface, input and output transducers disposed on the surface of the substrate, a coupler for coupling the transducers being spaced apart from the transducers on the surface of the substrate defining zones therebetween, and electric conductor runs being connected to the transducers on the surface of the substrate and having ends, includes a damping layer formed of photoresist material with a plastic base covering substantially the entire surface of the substrate except for a region bounded by the transducers, the coupler, the ends of the electric conductor runs and the zones between the transducers and the coupler, and a method for manufacturing the filter.

Abstract: A device for the high speed recording of photon images and nonrepetitive electrical waveforms which comprises a waveform recorder wherein surface acoustic waves excited in a can be GaAs, not layered piezoelectric-insulator-semiconductor layered structure produce a traveling electric field in the semiconductor substrate. Charges stored in the traveling potential wells and representing the instantaenous amplitude of a waveform to be recorded are transferred at static wells when a gate is dropped. Because each successive traveling well represents a different time instant of the waveform, the different spatial locations of the static wells correspond to different times. The output signal from the static wells 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: An impedance element formed from a single-port, surface acoustic wave transucer which generates a conductance versus frequency response characteristic having first and second peaks separated by a valley at a predetermined frequency and which generates a susceptance versus frequency response characteristic having a substantially constant portion over a finite bandwidth on both sides of said predetermined frequency.

Abstract: A surface acoustic wave device is provided for sensing the presence of chemical agents by chemo-electronic means. The device includes a quartz substrate and means deposited on the substrate for propagating and receiving surface acoustic waves along the surface of the substrate. Regions are provided on the substrate containing etched tunnels, the walls of the etched tunnel being coated within with a chemical substance sensitive to the chemical agent to be detected. When surface acoustic waves are caused to pass over these regions, the reaction of the chemical agent to be detected with the chemical substance causes a change in the acoustic wave velocity.

Abstract: A surface acoustic wave (SAW) convolver is provided for use in a communication system in which a received signal incorporates a mixed pseudonoise (PN) code sequence and narrowband information signal phase-modulated thereon according to a minimum shift keying (MSK) modulation scheme. The convolver includes a piezoelectric substrate capable of propagating acoustic wave signals on the top surface thereof, and a first transducer formed on the top surface for receiving the received signal and in response thereto generating acoustic surface waves along a first direction thereof. A second transducer is also formed on the top surface for receiving a reference signal and in response thereto generating acoustic surface waves along a second direction thereof, the reference signal incorporating the PN code sequence phase-modulated thereon according to a bi-phase shift keying (BPSK) modulation scheme. A BPSK-MSK converter integrally-formed on the substrate produces the reference signal in MSK form.

Abstract: The invention relates to an acousto-optical device comprising a laser source, positioned in the vicinity of the center of curvature of a spherical cap, formed from an elasto-optical, piezoelectric substrate. A piezoelectric transducer deposited on this substrate makes it possible to generate a surface sound wave, which propagates on the outer surface of the spherical cap. The signal diffracted by the substrate is collected on a line of detectors, placed in a plane close to the center of curvature of the cap.

Abstract: A surface acoustic wave processor capable of performing convolution, correlation, time expansion/compression, and time reversal utilizes the nonlinear interaction between two input surface waves to generate a third surface wave. Phase matching for the third surface wave to perform an integration function is provided by a fan multistrip coupler (FMSC) which appropriately alters the velocity of an electric field pattern transferred from one track of the FMSC to a second track thereof.

Abstract: A thick film device conductor arrangement suitable for making connections between a resiliently mounted element such as a surface acoustic delay line and adjacent thick film conductors and then with the device connecting pins. The thick film conductors include a double layer structure of differing noble metals each selected for desirable properties in designated areas of the device.

Abstract: An acoustic surface wave device having an acoustic energy absorber of acoustic surface wave absorbing material positioned between the input transducer and the output transducer. The acoustic energy absorber increases the insertion loss of the device and consequently suppresses triple transit signals in the device.

Abstract: In the manufacture of surface acoustic wave devices it is necessary to manufacture master patterns from which interdigitated electrodes are produced photographically. The manufacture of the master is expensive and a new master is needed for each new device required to operate at a different frequency. The invention overcomes this problem in the device shown in FIG. 1 by the use of transducers 2 and 5, each constituted by separate groups 3 or 6 of interdigitated fingers. The effect of this is for the transducer to have peak frequency responses at a whole series of frequency values. These frequency values can be shifted up or down by varying the velocity of the surface acoustic waves in the region of the appropriate transducer. This is done using any one of a number of different methods but, in the embodiment of FIG. 1, metal layers 8 and 9 are applied and then adjusted in size until a peak of the transducer 2 coincides, at the desired frequency, with a peak of the transducer 5.

Abstract: Low reflectivity electrodes (2-4) are formed within recesses extending from a major surface of a semiconductive and piezoelectric substrate (1) (such as gallium arsenide) so as to reduce SAW reflectivity from the electrodes.

Abstract: A surface acoustic wave (SAW) device configured to operate as a spectrum analyzer, and having an array of input transducers disposed on a substrate in such positions as to produce a focused beam of acoustic energy at a focal arc, each position on the arc being representative of an input signal frequency. Output transducers produce electrical signals corresponding to the energy received at successive segments of the focal arc. The disclosed device includes various combinations of input transducer array improvements, some of which are to provide amplitude weighting of the input array, including aperture width weighting, capacitive weighting, resistive weighting, series-parallel weighting, and source withdrawal weighting. Another improvement in input array configuration eliminates close or overlapping electrodes of opposite polarities and thereby reduces parasitic capacitance and acoustic radiation between electrode elements.

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: A surface acoustic wave (SAW) device is fabricated to minimize or eliminate purious signals caused by bulk modes. A backing layer is provided on the bottom surface of the crystal substrate of the SAW device having an acoustic impedance nearly the same as that of the crystal substrate for a family of spurious bulk modes.

Abstract: A signal processor for filtering unwanted narrowband noise from received wideband electrical signals also containing desired wideband noise is described. The signal processor includes means for partitioning the wideband received signal into a plurality of narrowband, noise-containing signals and for producing a plurality of narrowband output signals. The signal processor further includes means for monitoring each of the narrowband output signals and for reducing the voltage of any narrowband output signal when that signal exceeds a predetermined level. In the preferred embodiment, the monitoring means of the signal processor includes a plurality of voltage-regulating networks, wherein each network receives as a network input signal, a single one of said narrowband output signals into a detector and integrator network to produce an output command signal only when the voltage across a channel exceeds a predetermined level.

Abstract: An electrical device package comprising an open ended container and an enclosure defining a cavity in which an electrical device is contained. The enclosure is positioned in the container and is sealed therein by a filling of moulding material.The package is particularly suitable for containing surface acoustic wave devices e.g. filters where contact with the moulding material during and after packaging must be avoided.

Abstract: A surface acoustic wave apparatus comprises a surface acoustic wave element having one input electrode to which an input signal is supplied and two output electrodes, a variable gain element connected to the one output electrode, and an adder for adding the output of the variable gain element and the output of the other output electrode. The phase characteristic and the delay time characteristic of a filter determined by the input electrode and the one output electrode are the same as those of a filter determined by the input electrode and the other output electrode, respectively. Therefore, even if the amplitude-frequency characteristic of the adder varies, the phase characteristics and delay time are kept constant.

Abstract: A surface acoustic wave recording device is constructed for use in recording video signals in the surface of a master substrate. The device includes a pyramidal-shaped tip having a plurality of transducer electrodes for launching surface acoustic waves on the surfaces of the device structure. Surface acoustic waves launched from the plurality of transducers are focused at the apex of the record device. A stylus, for example, of diamond, affixed to the apex of the pyramidal structure vibrates in consonance with the signal to be recorded to cut the video signals into the surface of the master 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: An surface acoustic wave device, especially amplifier which includes input and output means for electrical signals provided so as to be spaced on a surface of a piezoelectric material which comprises a laminate in combination with a semiconductor, and an electrode provided in a surface signal wave propagation path between said input and output means for supplying pumping power.

Abstract: A broadband angle-beam transducer system for producing and/or receiving Reigh waves on the surface of a metal medium comprising a thickness mode piezoelectric polymer transducer element embedded within and impedance matched to a plastic wedge. The transducer element is oriented at an angle determined to be the critical angle for Rayleigh waves in the metal structure to be tested. As a transmitter, the transducer element generates discrete dilatational wave pulses, one of which propagates within the plastic wedge to the plastic face in contact with the metal structure. At this face some of the wave energy is reflected as dilatational and shear waves within the wedge and the remainder of the wave energy passes through a coupling medium into the metal structure producing a Rayleigh wave traveling along the surface of the structure.

Abstract: Pairs of input transducers are formed on the surface of a piezoelectric crystalline body. The input transducers in each pair produce adjacent parallel surface acoustic waves of opposite polarity and specific phase difference which are sensed by a corresponding output transducer. The input transducers of each pair are offset from one another by amounts related to the wavelength of the surface acoustic wave so that a maximum cancellation of the voltages induced in the output transducers by the acoustic waves can be used to indicate the relative delay or phase difference of signals applied to the input terminals and to do so in a manner which is insensitive to temperature variation from one point to another in the piezoelectric crystal.

Abstract: A compensation scheme is disclosed which avoids the requirement of high alignment accuracy, and thus reduces the production cost of a surface acoustic wave filter, by employing a compensating transducer system which is arranged with its fingers parallel to those of the receiving transducer. The requirement of receiver sensitivity at the trap frequencies is nevertheless achieved by using a very narrow compensating beam width. The narrowness of the compensating beam also allows it to pass directly through a multi-strip coupler. The degree of compensation achieved is controlled by aiming the compensating beam at a small region of the apodized receiving transducer located at the extremity of the major lobe; by restricting the aperture of the compensating transducer system; and by trimming the printed circuit capacitor which couples the compensating transducer system to the electrical input signal.

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: 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 broad band surface acoustic wave (SAW) device has an edge-deposited transducer (EDT) capable of frequencies in excess of 1 GHz and bandwidths in the hundreds of MHz. The device includes a transducer on a semiconductor substrate which is either non-piezoelectric or weakly piezoelectric. The substrate has a sharp, smooth edge formed by the intersection of its top and a side surface. The transducer includes a passivation layer deposited on the side surface of the substrate and a starter layer deposited on the passivation layer; an inner metallic (gold, for example) electrode deposited on the starter layer; a transducer layer deposited on the inner metallic electrode; and an outer metallic electrode deposited on the transducer layer. The outer electrode is formed on the transducer layer one-fifth wavelength below the top surface of the substrate.

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 multi-electrode array deposited on a piezoelectric substrate is driven by a traveling-wave voltage generated from a wave delay generating device, such as a tapped coaxial cable. Suitably delayed and phased voltages are fed to each electrode in the array. Surface acoustic waves are excited on the surface of the piezoelectric substrate. The surface acoustic waves travel through the array in proper phase with the exciting signal supplied to the electrodes. The surface acoustic waves pick up energy as they travel along the surface. Such a structure has a number of advantages over the prior art conventional interdigital transducers. For example, they exhibit broad bandwidth characteristics, have high conversion efficiency and are generally free of spurious signals. These advantages make them well suited for application to video disc cutterheads.

Abstract: A temperature stable surface acoustic wave device utilizes a known variation in the power flow angle characteristic of the substrate over a temperature range to vary the response of the device at one or more output transducers in a way which compensates for temperature dependent phase shifts common to prior art devices.

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: An acoustic surface wave device comprises a piezoelectric substrate (1), an input transducer (2), an output transducer (3) and acoustical absorbent layer patterns (5, 6) for absorbing undesired acoustic surface waves and bulk waves (S.sub.4, S.sub.5). Each of the acoustical absorbent layer patterns (5, 6) has zigzag-shaped or triangular shaped edges, i.e., a recess portion (R.sub.1, R.sub.3) and a protruding portion (R.sub.2, R.sub.4). The recess portion has a further recess portion (R.sub.1 ', R.sub.3 ') which is formed diagonally with respect to the propagation path of acoustic surface waves.

Abstract: For quantitative potential measurement of surface-wave filters, an alternating voltage with amplitude U.sub.E.sbsb.i is connected to an input transducer of the surface-wave filter. At a local region for measurement on the filter, an alternating voltage of amplitude U.sub.P arises. For each such measuring location, the voltage U.sub.P is compared to a nominal value and if it deviates therefrom, this deviation is utilized to control an amplitude of the input voltage U.sub.E.sbsb.i so as to maintain the voltage U.sub.P substantially constant. For the various measurement locations, the changes of the input voltage U.sub.E.sbsb.i are analyzed and a local attenuation factor for each measured region in the filter may be determined. By knowing a frequency of the driving alternating voltage, conclusions can be drawn concerning specific characteristics of the filter.

Abstract: A thin film metallic loop is used to electrically short the gap between metallic portions of a surface acoustic wave device to eliminate substrate surface cracks. The loop is deposited on the substrate at the same time the structures defining the gap are deposited.

Abstract: A surface acoustic wave device wherein a laminated structure comprised of a piezoelectric member and a metal electrode or electrodes is provided on a surface acoustic wave surface of an elastic body and an acoustic impedance discontinuous face is formed on the elastic body, so that a longitudinal wave generated by the laminated structure is reflected by the acoustic impedance discontinuous face to provide a transverse wave.

Abstract: The invention is an improved manufacturing technique for producing a certain class of Surface Acoustic Wave (SAW) devices, namely those having input and output transducers in close proximity. A much higher manufacturing yield results from eliminating the cutting of a slot in the substrate between input and output transducers as formerly done. This frequently destructive step is replaced by ion-milling of a deep groove between the ports and backfilling with a metal of proper configuration to provide electromagnetic shielding. The technique produces a new device that is at least equal to the prior art in rejection of unwanted couplings between input and output.

Abstract: A surface-acoustic-wave parametric device includes in that a plurality of pumping electrodes arranged along a propagation path of surface acoustic wave. Values of DC bias voltages to be applied to the respective pumping electrodes for forming parametric interaction regions, or values of pumping voltages to be applied to the pumping electrodes, are differentiated so as to correspond to a desired frequency characteristic.

Abstract: An improved surface acoustic wave device having an acoustic substrate is mounted on multidirectional deflection structures that provide isolation from shocks and vibration and permit thermal expansion without stress to the acoustic substrate.

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: 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: A surface acoustic wave device includes a piezoelectric substrate having opposite flat surfaces. On one surface of the substrate, there are provided launching transducer for launching acoustic waves and receiving transducer for receiving the launched acoustic waves. On the other surface of the substrate, there are provided a plurality of grooves aligned in an angled relation with the direction of propagation of the acoustic waves. The grooves are divided into two or more groups in which the depth of the grooves in one group is different from that in any other group.

Abstract: A surface acoustic wave gyroscope which detects a change in the propagation velocity of a surface acoustic wave as a function of the rotational velocity of a medium on whose surface the acoustic wave is propogated, is disclosed. In a first embodiment using a fixed frequency oscillator to generate the surface acoustic wave, the change in the propagation velocity is detected as a phase shift between the generated and detected waves. In an alternate embodiment the detected surface acoustic wave is used as a feedback signal to an amplifier to form an oscillator whose frequency varies as a function of the surface waves propagation velocity. In the preferred embodiment, two surface acoustic waves are generated in opposite directions about the cylindrical surface of a substrate.

Abstract: A piezoelectric device comprises a ferroelectric ceramic plate as polarized, and electrodes formed on two main surfaces thereof, respectively, intersecting the polarization axis direction. The electrodes are connected to each other by means of an external resistance having a predetermined resistance value. The resistance value is selected to be smaller than the inherent resistance value of the ferroelectric ceramic plate between the two main surfaces. The positive and negative electric charges are stored on the two electrodes due to the pyroelectric effect responsive to a change of the temperature of the ferroelectric ceramic plate. The potential difference caused by the electric charges thus stored is rapidly decreased through the external resistance.

Abstract: In-situ, non-destructive monitoring of semiconductors during laser annealing process is realized by a method the steps of which include: positioning a surface acoustic wave device adjacent to the semiconductor being annealed and in intercepting relationship with the annealing radiation, the surface acoustic wave device substrate being transparent to the annealing radiation; affixing an electrical contact to the top surface of the semiconductor; applying an r.f. input to the surface acoustic wave device; and measuring the transverse acousto- electrical voltage on the electrical contact. The surface acoustic wave propagation surface of the surface acoustic wave device is in close proximity to the bottom surface of the semiconductor and interaction of the electric field that accompanies the propagating surface acoustic wave with the charge carriers of the semiconductor produces the transverse acoustoelectric voltage. The transverse acoustoelectric voltage is thus a function of the semiconductor conductivity.

Abstract: An elastic surface wave device comprises a piezoelectric substrate having an input electrode and an output electrode on the surface, said input and output electrodes being in comb shape and opposing each other; a sound absorbing resin layer formed on at least part of the bottom surface of said piezoelectric substrate; and an adhesive resin layer in contact with said sound absorbing resin layer and said piezoelectric substrate for adhering said piezoelectric substrate to a stem.

Abstract: A method of making a humidity sensor which comprises an alumina substrate bearing a pair of noble metal electrodes. The electrodes are electrically connected to each other by an electrically conductive moisture-sensitive layer present on the substrate. In order to be able to monitor the moisture content of a gaseous atmosphere inside the housing of a sealed electronic device, for example an integrated circuit or an acoustic surface wave device, it is necessary to use a small sensor which can be used in a static atmosphere. According to the method, an electrode system may be formed by sputtering gold onto an alumina substrate. The substrate bearing the electrode system is then baked in air at a temperature in the range of from 100.degree. to 750.degree. C. for from 30 hours to 1/2 hour, and then a coating comprising orthophosphoric acid or phosphorus pentoxide is applied over that area of the substrate which is to bear the moisture-sensitive layer. The assembly is heated at from 50.degree. to 500.degree. C.

Abstract: A method and apparatus for generating and detecting acoustic surface waves particularly useful in the non-destructive testing of materials. In this method, the acoustic surface wave is generated in the test sample by a generator transducer coupled to the test sample so as to cause the acoustic wave to impinge on it at the required critical angle. The acoustic surface wave is detected by a pair of spaced steel wedges having their narrow ends in contact with the surface of the test sample so as to detect the shear component of the acoustic surface wave and to generate bulk waves in the steel wedges which travel away from the plane of the contact surface to pick-up transducers.

Abstract: An accelerometer comprising a mass 10 supported on a piezoelectric cantilevered beam 12 with SAW resonators 17, 46 disposed on the surface of the beam includes cover plates 66, 68 over the SAW resonators and sealed to the beam by seals 70, 72 which may be rigid (glass frit) or soft (filled polyimid).

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.