Abstract: A surface-acoustic-wave device wherein a plurality of metal strips (S) are provided on a propagation path of surface acoustic wave which is formed in a laminate comprised of a piezoelectric layer (23) and a semiconductor (1), the metal strips are extended onto the semiconductor outside the propagation path of surface acoustic wave, and depletion layer capacitance non-linearity created on the semiconductor surface at a region where the metal strips are extended is used as a main factor of a parametric interaction.

Abstract: A two track surface acoustic wave device is provided with a phase plate interposed between input and output transducers on one of the two tracks. An electrical coupler is connected across the output transducers to produce a sum signal at at least one of its outputs corresponding to surface waves making a single transit of each track. The coupler combines other signals having a different phase relationship--eg those corresponding to a triple transit of each track to give a null at one of these outputs. The coupler is connected into matched output loads to provide mutual isolation at its inputs. Tracks of different length may be used instead of the phase plate. Instead of electrical coupling, acoustic coupling may be provided between the two tracks to produce a similar result.

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: A surface acoustic wave device comprises a piezoelectric substrate, and an input transducer and an output transducer formed on the substrate. Dummy transducers are formed on the substrate and arranged to extend from the ends of the input and output transducers toward the ends of the substrate. The dummy transducers individually include electrodes spaced at the same pitch as the electrode pitch in the input and output transducers. Accordingly, there is no occurrence of reflections of the surface acoustic wave at the ends of the input and output transducers.

Abstract: A surface acoustic wave (SAW) device including a crystal substrate having two substantially planar surfaces and at least one SAW-to-plate mode coupler positioned on one of the surfaces. The SAW-to-plate mode coupler includes a plurality of parallel, linear surface perturbations. The surface perturbations are adapted to convert a portion of an incident SAW to a bulk acoustic wave (BAW). In addition, the coupler is adapted to convert a portion of an incident BAW (from the crystal bulk region) to a SAW at those surface perturbations. In addition, the planar surfaces of the crystal substrate are adapted to reflect portions of incident BAW's. The coupler is positioned with respect to the crystal characteristics so that SAW's and BAW's resonantly interact at the coupler. In alternative configurations, a second SAW-to-plate mode coupler is positioned on the second surface of the crystal substrate.

Abstract: A surface acoustic wave device comprising a piezoelectric substrate, an input transducer and an output transducer arranged diagonally to each other. A multistrip coupler is interposed between the input and output transducers. A reflecting transducer is placed opposite to the input transducer with the multistrip coupler therebetween. The multistrip coupler includes an adjusted number of conductors. The reflecting transducer includes weighted electrodes, and means for adjusting phase difference, whereby the surface acoustic waves reflected by the output transducer and the reflecting transducer are cancelled by each other. Accordingly, triple transit echo (TTE) can be suppressed without use of external variable resistors and inductors.

Abstract: A surface acoustic wave reflective array of the kind in which parallel rows of scatterers produce Bragg reflection of an incident wave in a wanted direction at a given frequency determined by the row spacing. The rows (4) are formed of scattering centers, eg metallized dots (11) divisible into unit structures (10) each containing a group of at least two such centers; the orientation and relative spacings (in terms of the Bragg wavelength) of the centers within each unit, relative to the direction (Z) of an incident beam, are such that the scattered waves constructively interfere in the wanted direction (X) while avoiding constructive interference in other directions. The scattering centers of each unit structure may be in the same row or in adjacent rows. The invention alleviates a disadvantage of existing reflective dot arrays, which tend additionally to produce reflections in unwanted directions.

Abstract: In order to avoid spurious responses at the third harmonic of the signal frequency, a surface acoustic wave filter employs a multi-strip track coupler in which the spacing d of the elements is an integral multiple I of the acoustic wavelength .lambda. of the third harmonic. When the condition d=I.lambda. is satisfied, the coupler blocks transmission of the third harmonic from the input transducer track to the output transducer track. This basic principle can also be used to block other frequencies.

Abstract: A surface acoustical wave (SAW) waveguide device which compensates for dispersion by utilizing diffused substrates. Various embodiments have in-diffused or out-diffused core regions in which the ray is channeled that are topped by a thin metallic film overlay. Partially surrounding each core region are cladding portions which are also selectively in-diffused or out-diffused and may be covered by the metal overlay. By varying the amounts of in-diffusion or out-diffusion for the particular application, the effects of dispersion are minimized.

Abstract: Microwave oscillator using magnetostatic surface or bulk waves which can be transmitted in a thin layer of magnetic material having two cavity resonators with coupled gratings of different equivalent lengths in such a way that the first is multimode and the second monomode in the reflection pass band of the gratings, the cavities being arranged in such a way that the second filters the modes transmitted in the first. Microwave signals are applied to one of the two cavities and the resonated waves are collected in the second cavity.

Abstract: In a conventional surface acoustic wave ring filter, a time-compensation element in the form of a thin strip is additionally provided for either retarding or accelerating one of the surface acoustic waves which transmit along different transmission lines, thereby the phases of two surface acoustic waves received by a single output converter included in the filter are matched with each other resulting in the improvement in the output signal characteristics.

Abstract: Energy trapping elements for use with shallow bulk acoustic wave devices of various kinds, to minimize the insertion loses in such devices due to spreading of electroacoustic energy into the crystal substrate upon which the devices are constructed. Electroacoustic energy propagated in a substrate is trapped close to the surface of the substrate by means of trapping elements comprising a plurality of strips or grooves disposed on the surface of the substrate in the path of the propagated energy, and oriented approximately perpendicularly to the direction of propagation. The spacing of the elements is such that their stop-band frequency, at which energy will be reflected, is substantially different from the characteristic center frequency of the entire device, in order that the elements will serve a purely trapping function and not a reflecting function.

Abstract: A frequency selector apparatus which effects a frequency selection by providing at least one reflecting electrode at a position adjacent elastic surface wave transducer or transducers provided in an acoustic wave propagation track in a piezoelectric medium so as to reflect a frequency component selected by a parametric interaction with an a.c. electrical signal applied to said reflecting electrode.

Abstract: An acoustic wave device comprises a substrate carrying two or more acoustic components aligned in different directions and electrically connected together in parallel. The phase slope of the acoustic components are similar but their temperature coefficients of delay are different whereby their resultant frequency response is compensated over a useful temperature range. The acoustic components may be delay line employing surface waves or surface skimming bulk waves, or one or two port resonators using surface waves.

Abstract: A surface acoustic wave (SAW) device including a crystal substrate having two substantially planar surfaces and at least one SAW-to-plate mode coupler positioned on one of the surfaces. The SAW-to-plate mode coupler includes a plurality of parallel, linear surface perturbations. The surface perturbations are adapted to convert a portion of an incident SAW to a bulk acoustic wave (BAW). In addition, the coupler is adapted to convert a portion of an incident BAW (from the crystal bulk region) to a SAW at those surface perturbations. In addition, the planar surfaces of the crystal substrate are adapted to reflect portions of incident BAW's. The coupler is positioned with respect to the crystal characteristics so that SAW's and BAW's resonantly interact at the coupler. In alternative configurations, a second SAW-to-plate mode coupler is positioned on the second surface of the crystal substrate.

Abstract: Preferred reflective surface wave processors employ cooperating serially disposed reflector sections. At least one reflecting section comprises an array of non-segmented reflecting grooves in which certain grooves are omitted to form a withdrawal array. Cooperatively coupled to this non-segmented array is an array of segmented grooves. The elements of the segmented array may be made up of progressively fewer segments in regularly spaced lines. The segments in any one segmented line may selectively be of equal lengths randomly spaced within a given line.

Abstract: A surface acoustic wave filter is disclosed having an interdigitated structure of transducer fingers on a piezo substrate. Spurious signals are suppressed by employment of a slanted placement of transducer fingers at an output region of a weighted input transducer or at an input region of a weighted output transducer.

Abstract: An elastic surface wave filter including on the surface of a plate, an emitting transducer, a surface wave coupler, and means for receiving the waves radiated by the coupler. The means for receiving includes two transducers each having two terminals with one terminal of each being in common with one terminal of the other. The common terminal serves as a phase reference and the voltages induced at the remaining terminals are in phase opposition to one another in the transmission band of the filter.

Abstract: The treatment is directly effected on the waves propagated. Zones, for creating interruptions in propagation, are created on the useful surface of the propagation material. Several parallel tracks for propagating the elastic waves are thus delimited by these zones, the length and width of which are selected in dependance upon the required treatment.

Abstract: The invention relates to an interaction device comprising a non-magnetic substrate, a thin easy-plane magnetic layer, two piezoelectric transducers arranged at the ends of the magnetic layer and respectively receiving the two electrical signals to be treated. The signals applied are converted into elastic surface waves which are transmitted to the magnetic layer in the form of magnetoelastic waves propagated in opposite directions. The device is subjected to an external magnetic field. The variations in magnetization in the interaction zone are collected by a detection plate and characterize the interaction between the two signals.

Abstract: A multiple track acoustic surface wave filter processes input signals successively flowing in coupled resonant acoustic tracks, each track being realized between pairs of surface wave reflectors in the surface of a planar piezoelectric substrate.

Abstract: Two input transducers launch oppositely-propagating acoustic surface waves on a piezoelectric substrate. The waves are compressed to a smaller beamwidth and then laterally confined in a diffused channel waveguide where non-linear interaction occurs at increased energy densities due to the beam compression. In one embodiment the beam compression is accomplished in multistrip couplers. In another embodiment, diffused horn-shaped channels are provided for compressing the beamwidth. Both piezoelectric and semiconductor convolvers are disclosed.

Abstract: This invention relates to a wave device comprising a single domain lithium niobate substrate having thereon a grating wherein the grating comprises single domain regions of lithium niobate having their plus c-axis direction substantially opposite the plus c-axis direction of the substrate.

Abstract: A reflective grating for a surface acoustic wave device is formed of interleaved sets of contiguous metal strips deposited on the surface of the device. The metal in one set of the strips has a density greater than that of the acoustic propagating medium of the device while the metal of the second set of strips has a density essentially equal to that of the acoustic propagating medium of the device. Typically, a piezoelectric material such as a crystal of quartz or a crystal of lithium niobate is utilized as the base material of the device with the grating being formed of an overlay of alternating strips of gold and aluminum.

Abstract: An acoustic surface wave signal transmission device includes a medium having a surface suitable for propagating acoustic energy or waves and having a first impedance characteristic. The surface of the medium includes an array of periodic discontinuities of a second impedance characteristic. The widths of the discontinuities vary in a predetermined manner to reflect a portion of said acoustic energy in proportion to the widths of the discontinuities. A transmitting transducer on said surface converts an input electrical signal into corresponding acoustic energy or waves and launches the energy or waves on said medium toward said array of discontinuities. The acoustic energy is reflected from said array of discontinuities toward a receiving transducer which converts the reflected acoustic energy or waves into a corresponding electrical signal.

Abstract: A sidestepping acoustic surface wave filter device employing a 3 dB multistrip coupler between the input transducer and the offset output transducer. A reflector is located across the track associated with the input transducer in the region adjacent to the output transducer. The 3 dB coupler causes the output transducer and the reflector to receive equal acoustic surface wave energy. The reflector is designed so that the energy reflected by it is equal to the energy returned by the output transducer. Phase shifts produced in the returning acoustic surface waves by the coupler cause the returning acoustic surface waves to be suppressed in the track associated with the input transducer. Thus, triple transit signals are avoided.

Abstract: Acoustic surface wave resonator structure in which coupling transducers are incorporated within reflecting arrays. Heretofore, acoustic surface wave resonator devices have included one or more interdigital transducers disposed in the resonant cavity between spaced arrays of reflectors in order to couple energy in and out of the device at resonance. The device disclosed incorporates the interdigital transducers into the reflector arrays themselves, rather than placing the transducers in the resonant cavity, thus allowing a total cavity size less than the total size of the transducers. The electrodes of the interdigital transducers incorporated into the reflector arrays are so arranged as to make these electrodes a periodic extension of the array.