Abstract: A bulk acoustic wave resonator is disclosed. The bulk acoustic wave resonator can include a ceramic substrate, and a piezoelectric layer on the ceramic substrate. The bulk acoustic wave resonator can also include first and second electrodes positioned on opposing sides of the piezoelectric layer. The bulk acoustic wave resonator can also include passivation layers that includes a first passivation layer and a second passivation layer. The first passivation layer can be positioned between the ceramic substrate and the first electrode. The second electrode can be positioned between the piezoelectric layer and the second passivation layer. The bulk acoustic wave resonator can further include a frame structure along an edge of an active region of the bulk acoustic wave resonator.

Abstract: Provided are a dual coupler device configured to receive lights of different polarization components, a spectrometer including the dual coupler device, and a non-invasive biometric sensor including the spectrometer. The dual coupler device may include, for example, a first coupler layer configured to receive a light of a first polarization component among incident lights. and a second coupler layer configured to receive a light of a second polarization component among the incident lights, wherein a polarization direction of the light of the first polarization component is perpendicular to a polarization direction of the light of the second polarization component. The first coupler layer and the second coupler layer may be spaced apart from each other and extended along a direction in which the light propagates in the first coupler layer and the second coupler layer.

Abstract: A delay line for an ultrasound transducer including: upper and lower surfaces, wherein the upper surface is configured to engage with an ultrasonic transducer and the lower surface is configured to engage with an object to be tested and the upper and lower surfaces have an area that is smaller than an area of the ultrasonic transducer; and at least one attachment face configured to attach to the ultrasound transducer.

Abstract: A face-lit waveguide illumination system employing a planar slab or plate of an optically transmissive material. A light source is optically coupled a linear optical element which is attached to a face of the waveguide and is configured to inject light at an angle permitting for light propagation by means of a total internal reflection. Light is propagated through the waveguide towards a predetermined direction in response to optical transmission and total internal reflection. Light extraction features located along the prevailing path of light propagation extract light from the waveguide and emit such light towards a surface perpendicular. In one embodiment, the planar waveguide includes a window pane which provides light transport from one location, where light is injected through the face of the pane, to another location where light is extracted. Additional embodiments of the face-lit waveguide illumination system are also disclosed.

Abstract: The invention relates to a device for compensating the temporary scattering applied to the generation of ultra-short light pulses, said device including two identical and parallel optical diffraction gratings RA, RB and two identical prisms PA, PB that are placed inside the above-mentioned optical diffraction gratings RA, RB, given that the above-mentioned optical diffraction gratings RA, RB are volume phase gratings that function, during transmission, on the principle of Bragg diffraction. The outer surfaces FeA, FeB of the above-mentioned prisms PA, PB are parallel to the above-mentioned optical diffraction gratings RA, RB, and the inner surfaces FiA, FiB of the above-mentioned prisms PA, PB are parallel therebetween.

Abstract: An electrical signal combiner includes at least one first element and a second element respectively connected to a first input port and to a second input port, and a third element connected to an output port, the electrical signals being propagated between the input and output ports. The combiner includes a medium; and the first, second and third elements are acoustic wave transducers, the electrical signals being carried by acoustic waves propagated between the input and output ports within the medium.

Abstract: A time-varying multi-path generating apparatus that generates time-varying characteristics of propagation path parameters, a multi-path fading simulator, and a multi-path generating method are disclosed. The generating apparatus for simulating multi-path fluctuations in radio communications consists of a parameter control unit for controlling generation conditions of propagation paths, a data storage unit for storing propagation path generation parameters and data files, and a propagation path generating unit for generating time-varying propagation paths. Multiple time-varying amplitude functions and multiple time-varying phase functions are generated based on the data files, the propagation path generation parameters, and random numbers generated by a random number generating unit. The time-varying amplitude functions are aligned serially in the time domain such that a time-varying shadow amplitude function is obtained, which is repeated N times where N represents the number of propagation paths.

Abstract: The invention relates to bus type connection systems, in particular those for wiring backplanes of electronic systems, when the bus comprises connectors distributed in an irregular manner. It consists in selecting segments (D1, D2) over which the intervals (d1, d2) between the connectors are substantially constant. The structure of all the segments except one is then modified to make the effective impedance of the modified segments coincide with that of the unmodified segment. It produces a bus that is fully matched from end to end and able to operate at a very high frequency with a slight reduction of its propagation constant.

Abstract: The present invention provides an RF model that characterizes the scattering hostility in an RF environment through a set of parameters. The parameters essentially provide a description of the amount of multipath that an RF signal would incur if it were to travel in the RF environment. Thus, such an RF model can be used to predict the amount of signal degradation that a given RF signal would experience when transmitted from any point in the RF environment. As a result, the RF model can be used to determine whether a given RF signal, if transmitted from a given point in an RF environment, could be received by a receiver located at another point in the RF environment. Advantageously, the RF model can characterize the scattering hostility in an RF environment without being programmed with volumes of environmental information.

Abstract: A circuit and method for automatically reducing an electrical path length difference between two electromagnetic signal paths. A counter converts the electrical path length difference to a multi-bit digital signal, and each bit in the signal operates a different one of plural switches which selectively inserts a time delay into one of the two electromagnetic signal paths to reduce the electrical path length difference. A comparator determines whether the electrical path length difference exceeds a threshold. The rectified AC component of a phase detector output is fed to the comparator which activates the counter when the threshold is exceeded. The counter drives the switched time delays in a sweeping fashion until the detected error falls below the threshold, whereupon the sweeping action is terminated.

Abstract: An identification and/or sensor system includes an identification and/or sensor configuration having resonators for determining at least one parameter to be interrogated. The resonators have a quality being good enough to effect a storage of energy in the resonators. A transmitting and receiving apparatus transmits interrogation signals by radio to the identification and/or sensor configuration and receives and evaluates reply signals transmitted back from the identification and/or sensor configuration. The transmitting and receiving apparatus is a broadband device.

Abstract: A waveguide for projecting a longitudinal acoustic wave of wavelength .lambda. from an ultrasound energy source toward a target area. The waveguide has at least one tubular channel. The channel has inwardly tapered, conical inlet and outlet ports separated by a venturi. The inlet port taper defines a sharply rimmed entry orifice around the inlet port. A separation distance equal to one wavelength .lambda. is maintained between the source and the waveguide's inlet port. The waveguide shears off a cross-section of the wave emitted by the energy source and ejects it at accelerated velocity toward the target area. The channel has a length L and the venturi has a diameter D, such that the waveguide has an emitted beam angle equal to 2 (tan.sup.-1 (D/L)). Preferably, a plurality of tubular channels are aligned concentrically around and longitudinally parallel to the one tubular channel, each channel having a selected length and a selected diameter.

Abstract: An electronic article surveillance system including a bulk acoustic wave transponder 10 coupled to an antenna 12, an interrogator 14, directional antenna 16 and an output connector 18. The transponder comprises a silicon or glass substrate 20, bus electrodes 22, 24, a launching IDT T0 and a series of "connected" and "unconnected" IDTs T1-T4. The connected/unconnected state of the respective IDTs T1-T4 may be detected and employed to generate an identification code comprising a series of binary digits. A thin copolymer piezoelectric film 26 covers the substrate 20 and electrodes T0-T4.

Abstract: A distributed temperature sensor comprises an elongate ultrasonic waveguide having a number of zones along its length, each zone having a grating formed on it. This is typically achieved by incorporating uniformly spaced notches or bands (or collars) throughout the zone. The grating spacing in each zone is different, so that each grating reflects a characteristic frequency. This frequency varies as the temperature of the zone varies, so if wide-band ultrasonic pulses are launched into the waveguide, the temperature of each zone can be determined from the reflected frequencies.

Abstract: A bulk acoustic wave spectrum analyzer and channelizer, using bulk acoustic wave beams in a body of material having the property of conducting bulk acoustic wave beams, including acoustically reflecting surfaces. An input transducer is positioned upon one surface of the body for launching acoustic beams into the body. At least one output transducer set, including a plurality of aligned, juxtaposed electrodes are placed on the outer surfaces of each of the output transducers of the transducer sets.

Abstract: An ultrasonic-wave delay line element comprises a pentagonal delay medium body formed by cutting at an angle of about 45.degree. a part of the major surface defined by a rectangular shape having two longer sides and two shorter sides, and has a pair of input and output electric-mechanic transducers provided on a side A formed by cutting the major surface. The input and output electric-mechanic transducers are attached to the cut side A at positions near longer side C contiguous to the cut side A with respect to the center of the cut side A; a reflection point for a sound-wave is provided in the cut side A while no reflection point is provided in a shorter side B contiguous to the out side A; two or more reflection points are provided in the longer side C; two reflection points are formed in the other shorter side D isolated from the cut side A; and four or more reflection points are provided in the other longer side E isolated from the cut side A.

Abstract: The disclosure relates to a small volume bulk acoustic channelizer, which does not utilize light and thereby avoids the shortcomings of light-related channelizers including limited dynamic range and poor response to short pulses. The device is essentially a bulk acoustic analogue of an optical spectroscope.

Abstract: There is disclosed a solid ultrasonic delay line comprising a solid ultrasonic delay medium on which polygonal multiple-reflective surfaces are formed. An input transducer for radiating longitudinal waves is disposed on one of the reflective surfaces. The longitudinal waves are transformed into transverse waves by other one of the reflective surfaces and then reconverted by yet other one of the reflective surfaces into longitudinal waves which enter an output transducer disposed on still other one of the reflective surfaces. Ultrasound absorbers cover at least portions of the main boundary surfaces perpendicular to the reflective surfaces. Spurious waves of the longitudinal waves radiated from the input transducer are transformed by the main boundary surfaces into transverse waves which enter the absorbers.

Abstract: A magnetostatic wave frequency analyzer apparatus utilizing forward volume waves. A single input transducer is arranged opposite a plurality of output transducers to receive the different frequencies of the generated magnetostatic forward volume wave. A geometric ground plane is positioned in the propagation path between the input transducer and the plurality of output transducers to demonstrate the propagation characteristics of magnetostatic forward volume waves (MSFVW) in the 2-6 GHz range. The waves were propagated in two inch diameter YIG La-doped films of varying thickness (20,30,40 microns). The waves were launched by the microstrip input transducers on an alumina substrate. Receiver transducers were also on the substrate, but placed approximately one inch away, in a semi-circle with 10 degrees of arc between adjacent transducers.

Abstract: An ultrasonic delay line fabricated from a solid transmission medium is configured to provide (2n+3) reflections of the desired signal at five reflective facets of an irregular polygon. The reflective pattern tends to allow maximum surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions. In an alternative embodiment, a bifurcated delay line includes two branches physically coupled at one end and electrically coupled through a pair of transducers so that approximately half the height and width of transmission medium is required in order to effectuate a predetermined time delay.

Abstract: A transmission-type electro-acoustic delay line comprises an acoustic medium delimited by a cylindrical lateral surface, a plane terminal surface on which are fixed two symmetrical transducers, and a focusing terminal surface in the form of a spherical cap. The angle formed by the plane surface and the axis of revolution of the spherical cap is less than 90.degree. by an angle such that the incident acoustic wave undergoes a single reflection on the focusing cap and such that the reflected acoustic wave is concentrated at the level of the output transducer.

Abstract: A bifurcated electroacoustic delay line exhibits at least a pair of substantially identical branches, each assuming a generally pentagonal profile. Each branch is configured to provide (2n+3) reflections of a desired wave at five reflective facets. The reflective pattern so defined tends to maximize the surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions.The branches are physically joined along at least one side and include transducers for the conversion of electrical energy to acoustical energy. An inductance connected between two such transducers couples energy from one branch to the other.

Abstract: Comb filter having a comb like band pass characteristic curve by using an ultrasonic delay line (9) is improved to reduce its size. An input signal is given through an impedance element 13 to a single terminal 10a of an improved delay line 9, wherein the single terminal serves as the input terminal and at the same time as the output terminal. Signals at both ends of the impedance element 13 are given to a mixing circuit 15 for summing or subtracting thereby. In the improved delay line 9, the ultrasonic wave radiated from the input terminal travels twice the conventional delay line and comes back to the original terminal, and thereby a sufficient propagation distance is obtainable in a small delay line.

Abstract: A bifurcated electroacoustic delay line exhibits at least a pair of substantially identical branches, each assuming a generally pentagonal profile. Each branch is configured to provide (2n+3) reflections of a desired wave at five reflective facets. The reflective pattern so defined tends to maximize the surface area available for the deposition of absorbent material so as to thereby and otherwise minimize spurious transmissions.The branches are physically joined along one side so as to define an area of bifurcation. A plurality of piezoelectric transducers are bonded at the area of bifurcation in a pairwise laterally adjacent manner. An inductance couples electrical energy from the output transducer of the first branch to the input transducer of the second branch.

Abstract: A bifurcated electroacoustic delay line includes first and second branches of a transmission medium, the branches being joined along respective common sides. Bonded to the common sides of the branches are respective first and second input and first and second output transducers, the transducers arranged so that the input transducers are positioned laterally adjacent each other and the output transducers are analogously positioned. An inductance diagonally couples the first output transducer to the second input transducer permits frequency tuning of the delay line.Diagonal coupling via an inductance operates to mitigate the effects of spurious responses derived from the divergence of electroacoustic waves between laterally adjacent tranducers and, collaterally, permits tuning of the delay line composite frequency response.

Abstract: There is disclosed a solid ultrasonic delay line which comprises a delay medium having two parallel major faces and at least three end faces intersecting the major faces, an input transducer bonded to one of the end faces and polarized in a direction parallel to the major faces for transmitting an ultrasonic signal in a shear mode into the delay medium, and an output transducer bonded to one of the end faces for converting the ultrasonic signal having propagated through the delay medium into an electrical signal. The input and output transducers have boundary surfaces lying flush with the two major faces of the delay medium, the major faces and the boundary surfaces being ground to a surface roughness which is one-twentieth or smaller of the wavelength of the ultrasonic signal propagating through the delay medium.

Abstract: An acoustic superlattice of alternating layers of different acoustic impedance is disclosed as a filter for high frequency phonons. Applications discussed include spectrometers, acoustic imaging apparatus, and cavity resonators.

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: The invention relates to a magnetostatic-wave device whose ferrimagnetic layer supports an exchange structure formed by an array of conducting strips having their ends connected by conducting bridges. The invention applies particularly to the construction of magnetostatic-wave devices using couplers, hybrid junctions, reflecting mirrors, extraction structures and resonators.

Abstract: In a miniaturized delay line constituted by a single crystal through which an ultrasonic beam passes and by two electroacoustic transducers, the direct coupling between the input and the output of the delay line is attenuated by means of a molded shielding element of araldite loaded with silver. The molded element is placed around the output transducer as well as the lead which connects the transducer to one of the connector-pins of the base of the casing containing the delay line.

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.