Abstract: A surface wave device, for use in differential coherent detection in a commutation signaling communications system using N predetermined M-bit codewords, propagates surface waves for each codeword to a first coded output IDT (inter-digital transducer) comprising M parallel taps with a pitch t=T/M, the taps having phases representing bits of the respective codeword, and to a second output IDT which is at a distance from an input IDT greater by T than the first coded output IDT, to provide an additional delay of one information symbol. The input IDT, or each tap of each coded output IDT, has a length equal to t. The second output IDT can comprise a coded IDT, or a delay tap responsive to the surface wave propagated via the first coded output IDT.

Abstract: A surface acoustic wave filter device suitable for CDMA communication system includes a piezoelectric substrate, and a unidirectional input side transducer and a bidirectional output side transducer are formed on the substrate. The filter device has satisfactory filtering characteristics in terms of insertion loss, frequency characteristics, T.T.E. attenuation level, group delay time, etc.

Abstract: A surface acoustic wave filter according to the present invention is constructed by connecting in series one or two or more filter functional units each comprising a first surface acoustic wave resonator having input and output terminals connected in series with a signal line and a second surface acoustic wave resonator having input and output terminals one of which is connected to the signal line and the other of which is grounded. The first surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically open strip type grating reflectors with the interdigital transducer interposed therebetween, and the second surface acoustic wave resonator is constituted by one interdigital transducer and a pair of electrically short strip type grating reflectors with the interdigital transducer interposed therebetween.

Abstract: A SAW filter comprising a group of N tracks, where N is an odd integer greater than 2, and including an input interdigitated transducer (IDT) spaced apart from an output IDT. The respective tracks are selectable to have different effective electro-acoustic lengths such that surface acoustic waves launched from respective input IDTs undergo at least one reflection at corresponding output IDTs and at least one reflection from the respective input IDTs prior to generating coherent signals from respective output IDTs. The different effective electro-acoustic lengths may be substantially provided by there being different physical separation between input and output IDTs of respective tracks, or by IDTs of respective tracks having different polarity connections of electrodes or different amounts of material deposited in respective tracks between the input and output IDTs.

Abstract: A demodulation apparatus and a communication system using the same are disclosed. The apparatus comprises code generation means for generating a reference spread code corresponding to a first signal modulated by a spread code, and an elastic surface wave element for receiving the first signal and a second signal output from the code generation means, and outputting a demodulated information signal.

Abstract: An acoustooptic device includes a Y-cut and Z-propagation LiNbO.sub.3 substrate or 128.degree.-rotating Y-plane LiNbO.sub.3 substrate, an optical waveguide layer which is formed on at least a part of the LiNbO.sub.3 substrate and has a higher light refractive index than the LiNbO.sub.3 substrate, an interdigital electrode which is formed on the LiNbO.sub.3 substrate and generates Rayleigh waves, and a dielectric thin film layer formed on the interdigital electrode.

Abstract: A transponder antenna is carried by a substrate and is sandwiched between the substrate and a cover sheet. A rectangular opening extends through the cover sheet and receives a signal processing chip adhesively carried in a recess below a cap which covers the opening. The chip is spaced with respect to the antenna so as to facilitate inductive coupling between the chip and antenna.

Abstract: In a television receiver a SAW filter (FSAW) is preceded by a coupling network (CNW). The coupling network (CNW) includes an inductor (LP) between two input terminals of the SAW filter (IS1, IS2). It further includes a series resonance circuit (SRC) coupled to at least one of the input terminals (IS1). In order to reduce signal distortion a resistor (RP) is coupled between the two input terminals (IS1, IS2). Alternatively, a resistor (RS) is coupled in parallel to the series resonance circuit (SRC).

Abstract: A method and apparatus for a ladder filter (300, 400) incorporating same. The filter (100) includes a substrate and a first series resonator (100, 305, 403) disposed on the substrate and electrically coupled in series between the first electrical port (301, 401) and a first node. The first series resonator (100, 305, 403) includes a first series acoustic reflector (303), a first series gap (112), a first series transducer (105, 304, 403), a second series gap (112) and a second series acoustic reflector (115', 306) collectively disposed in an in-line configuration along a principal axis of the substrate. The filter (300, 400) also includes a first shunt resonator (100', 310, 404) disposed on the substrate and electrically coupled in shunt between the first node and ground.

Abstract: A surface acoustic wave device is designed such that an inter-digital transducer and a reflector have the same grating cycle. The electrode dye width of the reflector is larger than that of the inter-digital transducer, or the electrode dye width is smaller than the distance between the electrodes by changing at least one of the inter-digital transducer and the reflector. Connecting the thus structured surface acoustic wave devices to a single piezoelectric substrate as resonators in a ladder form produces a surface acoustic wave device for use in a filter.

Abstract: A method and apparatus for an acoustic wave filter (110) with reduced bulk-wave scattering loss and a ladder filter (30, 40) incorporating same. The method includes steps of providing an acoustic wave propagating substrate (111) and disposing a first reflector (112) on a first surface thereof. The method also includes disposing a first transducer (115) to a first side of the first reflector (112). The first transducer (115) is separated from the first reflector (112) by a first gap (118) having a first width (114) exceeding one-fourth of the acoustic wavelength. The method also includes disposing a second reflector (112') to a side of the first transducer (115) opposite the first reflector (112). The first (112) and second (112') reflectors each include a group of periodically disposed reflective elements (113, 113'). The second reflector (112') is separated from the first transducer (115) by a second gap (140) having a second width (139).

Abstract: A three-terminal resonator device (200) resonant at a resonant frequency has a first terminal (201), a second terminal (202), and a common terminal (203). The resonator includes a surface acoustic wave transducer (290) disposed on a piezoelectric substrate (201). The SAW transducer (290) is comprised of a first sub-transducer (210) and a second sub-transducer (220) which respectively include a first set of electrodes (211,213) and a second set of electrodes (221,223). One of the electrodes of each of the first set and the second set of electrodes respectively provide the first terminal (201) and the second terminal (203). The other terminals of the first and second set of electrodes are connected at the common terminal (203) to provide a serial connection between the first sub-transducer (210), and the second sub-transducer (220).

Abstract: A surface acoustic wave device comprises, on a lithium tetraborate substrate 10, a central interdigital transducer 21, 31, and first and second interdigital transducers 22, 23, 32, 33 disposed adjacently on both sides of the central interdigital transducer 21, 31 in a propagation direction of surface acoustic waves, or comprises a first such row of transducers 20 and a second such row of transducers 30 connected in cascade to each other. A sum Nc+Ns of a number of the central interdigital transducer pairs Nc, and a total number of the first and second interdigital transducers pairs Ns is set at a suitable range. The surface acoustic wave device has flat group delay times, relatively wide specific band widths, small insertion losses and large attenuation outside the pass band.

Abstract: A SAW resonator disposed with an IDT electrode and reflector electrodes is formed on the surface of a piezoelectric substrate. Three pieces of the SAW resonator form an acoustic coupling by being disposed close to each other, electrode fingers comprising the IDT electrode in the center are all grounded, and IDT electrode fingers are electrically independent on the side to be connected to input-output terminals of the IDT electrodes disposed outside. As a result, three excitation modes having different propagation frequencies are generated which are used to attain a broad band SAW resonator filter. When these three pairs of the IDT electrode are electrically independent, a balanced input-output can be achieved, and excellent out-of-band rejection characteristics can be obtained.

Abstract: An IIDT type surface acoustic wave filter (41) comprising a piezoelectric substrate and at least three IDTs (44 to 46) which are arranged on a surface of the piezoelectric substrate along the direction of surface wave propagation, the IDT (44) being inverted in phase with respect to the other IDT (46) while these IDTs (44) and (46) are connected in series to each other through the ground potential, thereby balancing inputs or outputs.

Abstract: The invention concerns unidirectional ground-wave transducers using an alternating series of emitter cells (E) and reflector cells (R).The invention consists in using, in the emitter cells (E), fingers having a width of .lambda./3 spaced apart by a distance of 2 .lambda./3; and, in the reflector cells (R), fingers having a width of .lambda./4 spaced apart by a distance of .lambda./2.Using identical engraving precision, the invention makes it possible to increase by 50% the frequency at which the unidirectional transducer thus produced can be used.

Abstract: An SAW filter includes an SAW substrate and input and output IDTs which are arranged on the SAW substrate at a prescribed distance from each other. The IDTs are provided on outer end portions along the surface wave propagation direction with electric field concentration relaxation electrodes extending from pairs of bus bars inwardly along oblique directions.

Abstract: An acoustic wave device in which the propagation path of the surface acoustic wave device is folded to increase the wave propagation path length in order to make better use of the total chip space.

Abstract: A SAW substrate is disclosed which can be adapted to a particular signal in multitude of signal possibilities. Each signal adaptation is made by connecting alternate electrodes of sequential tap transducers to either a positive bus or a negative bus, through auxiliary buses. A pair of the auxiliary buses is dedicated to each tap transducer, with one auxiliary bus in each pair being disposed adjacent to the positive bus and the other auxiliary bus in each pair being disposed adjacent to the negative bus. A pad is associated with each auxiliary bus for locating it adjacent to the positive bus or the negative bus which is not otherwise adjacent thereto. When a large number of signal possibilities are necessary, an unreasonably lengthy substrate is avoided by aligning the tap transducers in parallel channels across the substrate.

Abstract: A surface acoustic wave interdigital transducer of a filter includes split finger electrodes in pairs. To achieve a desired transfer characteristic that is either symmetrical or deliberately asymmetrical, a number of the pairs of the split finger electrodes are replaced by single finger electrodes.

Abstract: A three electrode type SAW longitudinal coupling filter includes a piezoelectric substrate having an electromechanical coupling factor (K.sup.2) higher than 10% and, three sets in total of input electrodes and output electrodes. Each of the electrodes includes a plurality of a electrode fingers of comb shape and are formed on the piezoelectric substrate. Reflectors are disposed at opposite sides of the input electrodes and output electrodes. The number of pairs of electrode fingers of the input electrodes is differentiated from the number of pairs of electrode fingers of the output electrodes. By the above arrangement, a large pass-band width can be obtained with small ripples and with an increase of the attenuation amount outside the band region.

Abstract: To obtain a surface acoustic wave device which can be produced with ease at a low cost and can be reduced in size without causing deterioration of characteristics, a surface acoustic wave device having input and output transducers arranged alternately on the surface of a substrate for propagating a surface acoustic wave includes metal patterns provided outside the transducers along the extension line of the propagation path of the surface acoustic wave and having at least one surface inclined at an angle .theta.(5.degree.<.theta.<85.degree. or -85.degree.<.theta.<-5.degree.) with respect to the propagation direction of the surface acoustic wave.

Abstract: A chemical sensor includes a piezoelectric support (1) capable of supporting a shear horizontal wave provided on its surface with an electrode (2,3). The sensor is characterized in that the surface of the piezoelectric support (1) including the region bearing the electrode (2,3) is covered by a layer of dielectric material (9) of thickness 0.5 to 20 microns. The piezoelectric support (1) is preferably a single crystal. The dielectric layer (1) may be of, for example, silicon dioxide or a suitable polymer, and preferably has a thickness of between 0.5 and 5 .mu.m.

Abstract: A surface acoustic wave device includes a piezoelectric substrate, a wave guide path provided on the piezoelectric substrate and an interdigital transducer for exciting a surface acoustic wave. The interdigital transducer is provided with plural portions of mutually different pitches of the electrode finger, respectively corresponding to different frequencies. The portions are parallelly arranged along a direction perpendicular to the propagation direction of the surface acoustic wave. The surface acoustic wave generated by the interdigital transducer is entered in concentrated manner into the wave guide path.

Abstract: An electronic apparatus for receiving and filtering high frequency waves comprises a sequence of T electro-acoustic transducers each having multiple interdigital electrode fingers and a centerline located equidistant between its outermost electrode fingers. For a centerline-to-centerline distance of a first adjacent pair of transducers D.sub.1, and centerline-to-centerline distances of other adjacent pairs of transducers D.sub.2 to D.sub.T-1, then at least some of D.sub.2 to D.sub.T-1 differ from D.sub.1 by a non-integral number of wavelengths. The transducer array is symmetrical about a centerline and the number of fingers in each transducer varies, with an input or output transducer closer to either end of the sequence having more fingers than a like kind transducer nearer the center.

Abstract: This invention relates to analyte-responsive compositions and analyte detection methods using these compositions, and, more particularly, to such compositions based on potassium titanyl phosphate (KTP) and analogs thereof and to analyte detection methods based on piezoelectric and optical properties of materials.

Abstract: A surface acoustic wave filter device includes a substrate which includes quartz or the like piezoelectric material having a small temperature coefficient. The substrate has a surface which is formed with interdigital-type unidirectional transducers on input and output sides, each having a positive electrode and a negative electrode. The positive electrodes and the negative electrodes of each of the input side and output side transducers have electrode fingers which are arranged so as to transduce a harmonic wave of a selected order which is higher relative to a fundamental surface acoustic wave.

Abstract: An acoustic wave filter with reduced bulk-wave scattering loss has a center frequency and an associated acoustic wavelength. The filter includes a substrate and a first reflector having a first group of periodically disposed reflective elements. The filter includes a first transducer on a first side of the first reflector. The filter also includes a first gap having a first width, located between the first reflector and the first transducer. The first width exceeds one-fourth of the acoustic wavelength. The filter includes a second reflector and a second gap disposed between the first transducer and the second reflector. The second gap has a second breadth exceeding one-fourth of the acoustic wavelength. A first waveguiding element is positioned within the first gap and having a first breadth. The first width exceeds the first breadth.

Abstract: A includes a non-piezoelectric substrate and a piezoelectric substrate (206) having matched transducers on both opposed surfaces of the piezoelectric substrate (206). The matched transducers being 180 degrees out of phase from one another. The present invention provides for improved coupling due to the new SAW the multilayer transducer topology.

Abstract: A novel surface acoustic wave device that includes a multiple track transducer having a first portion for generating a transverse symmetrical mode acoustic wave and a second portion for receiving only a transverse nonsymmetrical surface acoustic wave such that substantially no direct coupling occurs between the first and second portions of the multiple track transducer and where reflector gratings are mode changing gratings that reflect the transverse symmetrical wave as a transverse nonsymmetrical wave that is received by the second portion of the multiple track transducer thereby substantially reducing undesired in-band surface acoustic wave transducer responses as well as spurious bulk responses and allowing a narrow passband to be obtained with a short structure when compared with the prior art structures.

Abstract: A complementary acoustic charge transport circuit element comprises first and second buried channels. Each of the channels is comprised of a piezoelectric semiconductor and each channel has a source through which charge is injected and a drain through which charge is extracted. A transducer propagates an acoustic wave through each channel and the propagated waves transport the charge between the sources and the drains. A source and/or a drain of one channel is connected in parallel with the corresponding souce and/or drain of the other channel. The waves are complementary at the interconnected ones of the sources and/or the drains.

Abstract: An article of manufacture is provided including a substrate having an oxide surface layer and a selective thin film of a cyclodextrin derivative chemically bound upon said substrate, said film is adapted for the inclusion of a selected organic compound therewith. Such an article can be either a chemical sensor capable of detecting a resultant mass change from inclusion of the selected organic compound or a chemical separator capable of reversibly selectively separating a selected organic compound.

Abstract: Devices for controlling high frequency signals such as optic or electric signals are disclosed which utilize guided and/or reflected surface acoustic waves. The devices preferably use crystalline substrates modified (e.g., by ion exchange to increase mass density) to contain acoustic reflectors and/or continuous acoustic waveguiding channels (optionally, in combination with optical features such as optical waveguiding channels) and interdigital transducers deposited thereon to provide frequency generation (and reception where high frequency electrical signals are controlled). The preferred crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves, such as MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.

Abstract: A surface acoustic wave device which can operate at a higher frequency range is produced by irradiation with a focused ion beam to produce a narrower electrode width and narrower spacing width between neighboring electrodes in contact with a piezoelectric body, without degrading the reliability of the device. The surface acoustic wave device includes a piezoelectric body 3 and interdigital electrodes 2a and 2b in close contact with the piezoelectric body 3 and formed by using the focused ion beam. In order to increase the frequency of the device, the piezoelectric body 3 may be formed on a substrate 1, for example of diamond.

Abstract: An interdigital transducer is weighted by means of finger-width weighting for surface wave arrangements. The weighting is produced by differing finger widths in conjunction with constant widths of finger gaps. Constant finger overlap length is preferably provided.

Abstract: In a surface acoustic wave filter utilizing at least two longitudinal modes, input and output interdigital transducers are mounted on a piezoelectric substrate so as to oppose each other. First and second grating reflectors are mounted on the piezoelectric substrate outside the input and the output interdigital transducers, respectively. Each of the input and the output interdigital transducers comprises a plurality of electrode digits which are equal to N in number. Each of the electrode digits is made of a metal material having a discontinuous impedance coefficient K related to acoustic impedance. The surface acoustic wave filter is structured so that a product of the number N and the discontinuous impedance coefficient K is not smaller than 0.55.

Abstract: A surface wave reflection filter includes an input transducer, an output transducer, and a reflector in a first propagation track. To compensate for undesired surface waves proceeding directly between the input and output transducers, as opposed to the desired surface waves which are reflected before reaching the output transducer, a second propagation track is provided. The second track includes a input transducer and an output transducer, and is either connected in phase opposition to compensate for the undesired signal, or is constructed to generate a signal in phase opposition. A sump may be provided in the second track, a second reflector may be provided in the first track or in the second track, and the two tracks may be on separate or the same substrates.

Abstract: A surface acoustic wave device includes a piezoelectric substrate, an input electrode formed on the substrate and an output electrode formed on the substrate. A surface acoustic wave is generated from the input electrode to propagate in a predetermined direction in accordance with an input signal. In the output electrode, a plurality of taps are arranged in a propagation direction of the surface acoustic wave on the substrate. The surface acoustic wave is converted into an electrical signal by the output electrode. The taps of the output electrode are weighted so that signals output from the taps have substantially equal magnitudes.

Abstract: A surface acoustic wave element is provided with a piezoelectic substrate, a first input transducer, a second input transducer and an output device such as output electrode. The piezoelectric substrate has a first and a second surfaces which are mutually faced. The first input transducer is formed on the first surface of the substrate to generate a first surface acoustic wave which propagates in a predetermined direction. The second transducer is formed on the first surface of the substrate to generate a second surface acoustic wave which propagates in a direction opposite to the predetermined direction. The output device is formed on the first surface of the substrate to extract a signal produced by an interaction of the first and second surface acoustic waves. At least part of the second surface of the substrate is caused to be inclined in a direction perpendicular to the predetermined direction with respect to the first surface.

Abstract: A double mode surface wave resonator comprises two IDTs (inter-digital transducers), arranged side by side between reflection gratings, on a surface of a piezoelectric substrate to provide for coupling of surface waves therebetween, each IDT having interleaved electrodes extending from a common rail between the two IDTs and from a respective outer rail of the IDT. One or each of the IDTs and its outer rail is divided into two halves for providing a differential signal connection to the resonator. The electrodes of the IDTs can be arranged in spatial synchronism with adjacent fingers of the reflection gratings to reduce spurious longitudinal modes.

Abstract: A SAW filter structure (300) includes two SAW resonators being symmetrically positioned along parallel tracks. The resonators include centrally positioned resonator gaps (368, 378) which are opposingly positioned. A multistrip coupler (330) for acoustically coupling the resonators extends between the resonator gaps and includes a plurality of equally spaced strips (8812) which are spaced to permit omni-directional projection of acoustic waves from the opposing sides of the multi strip coupler.

Abstract: A SAW resonator/filter structure (300) includes a transducer portion. The transducer portion includes a plurality of acoustically coupled sub-transducer portions (310 and 312) comprising conductive patterns having interdigitated open-ended fingers. The sub-transducer portions (310 and 312) are electrically coupled to each other in series in order to increase the port impedance of the SAW filter structure (300) while providing the widest bandwidth.

Abstract: Devices are disclosed for controlling high frequency signals such as optic or electric signals by the generation of acoustic waves. The devices use certain bulk or surface-modified crystalline substrates which have a surface with a receiving area and an input interdigital transducer deposited on the signal receiving area of the substrate surface which is suitable for connection to a source of signal and for inverse piezoelectrically generating acoustic waves in the crystalline substrate. The crystal substrates are of a material having a piezoelectric-elastic dielectric matrix capable of the generation of acoustic waves and for bulk substrates, are of MTiOXO.sub.4 (where M is K, Rb, Tl, and/or NH.sub.4 and X is P and/or As) having mm2 symmetry.

Abstract: In a surface acoustic wave transducer having closely space-apart IDT electrode segments, a metallic oxide is selectively formed only along the marginal edge of each electrode segment so that it separates adjacent electrode segments, thereby preventing short-circuiting therebetween, permitting easy fabrication of the transducer and improving the yield rate of fabrication.

Abstract: An interdigital transducer for use in a surface acoustic wave filter has two busbars of an irregular shape to reduce the effect of internally reflected surface waves. The busbars will usually have an identical shape to one another and have stepped outer and inner edges. The distance between a portion of the outer edge and a corresponding portion of the inner edge can be constant for a particular busbar or that distance can vary. With previous busbars, the outer and inner edges are linear and each busbar has a rectangular shape.

Abstract: A surface acoustic wave convolver includes first and second interdigital electrodes for exciting surface acoustic waves and an output electrode for detecting the surface acoustic waves to extract a convolution output as an electrical signal, the first and second interdigital electrodes and the output electrode being formed on a piezoelectric or electrostrictive substrate.

Abstract: In an interdigital electrode of a surface acoustic wave device having nonexciting portions formed by removing fingers, fingers having an excitation source located nearest to a nonexciting portion in between are so positioned as to approach the nonexciting portion as compared with arrangement pitch of other fingers. Fingers having an excitation source located nearest to an end of the electrode in between are so positioned as to approach the end of the interdigital electrode as compared with arrangement pitch of other fingers. Fingers having an excitation source located in the central portion of the electrode group in between are so positioned as to approach each other as compared with arrangement pitch of other fingers.

Abstract: A reflector arrangement for an acoustic wave device comprises an acoustic wave propagating substrate, reflection elements having at least two different widths separated by at least one gap breadth disposed on the acoustic wave propagating substrate. The at least two different widths enhance reflected waves produced by the propagating acoustic wave in such a fashion as to achieve a total acoustic reflectivity which is independent of variations in width of the reflection elements.

Abstract: A sensor for chemical vapor detection using a surface acoustic wave (SAW) ray that provides a means for simultaneously detecting several chemical agents. The sensor has a piezoelectric substrate and a bidirectional surface acoustic wave transducer on the substrate. Also on the substrate are several pairs of identical acoustic sensing and reference channels each on opposite sides of the transducer in a mirror image fashion. Each channel pair has a thin film capable of absorbing a chemical vapor to be monitored and a metallic surface acoustic wave grating reflector capable of receiving and reflecting surface acoustic waves through the thin film and back to the transducer. An acoustic absorber separates each channel. The reference channels are protected from ambient conditions while the sensing channels are exposed to such conditions. An RF signal is applied to the transducer causing the propagation of an acoustic signal into each of the sensing channels and reference channels.

Abstract: A surface-acoustic-wave device comprises a substrate of a piezoelectric material for providing a passage of surface acoustic waves at an upper major surface of the substrate, a plurality of interdigital electrodes provided on the piezoelectric substrate in a row in correspondence to the passage of surface acoustic waves such that the electrodes are aligned in the propagating direction of the surface acoustic waves, each of the plurality of interdigital electrodes having a first part connected to a bonding pad on the substrate for external electric connection and having a plurality of finger electrodes extending parallel with each other in a direction crossing the propagating surface acoustic waves, and a second part separated from the first part and having a plurality of finger electrodes extending parallel with each other in a direction opposite to the direction of the finger electrodes of the first part.