Abstract: A ladder-type film bulk acoustic resonator (FBAR) filter comprises two series FBARs and two parallel FBARs. Each FBAR has a top electrode, a bottom electrode, and a piezoelectric layer sandwiched between the top and bottom electrodes. The top electrodes of the two series FBARs form part of a signal line of a coplanar waveguide transmission line. The top electrodes of the two series FBARs are connected to associated circuitry. The two series FBARs have a common bottom electrode.

Abstract: Multiple thin film bulk acoustic resonators (10, 11) configured in series (10) and parallel (11) within a coplanar waveguide line structure provides a compact ladder filter. The resonators (10, 11) are formed over an opening (28) in a substrate (20) and connected to associated circuitry by one or more transmission lines formed on the substrate (20). The arrangement of the resonators (10, 11) between the ground and signal lines of a coplanar line structure provides a means of minimising the area of the filter. Embedding a ladder filter within the coplanar transmission line structure eliminates the need for wire bonds, thus simplifying fabrication. Embodiments for 2×2, and hither order filters are described.

Abstract: A method and apparatus for the spatial distribution of a filler component within the matrix of a composite material. An electric field is applied to a mixture consisting of two or more components that have different dielectric permittivities, at least one of which is initially in the form of a liquid polymer or pre-polymer. An alternating electric field is established between a pair of electrical conductors or electrodes that are moved relative to each other, so as to alter the spatial intensity of the electric field in a controlled manner. Polarized particles or elements of the filler component that are coupled to a moving electrode by a dielectrophoretic force can consequently be dragged into a predetermined spatial configuration. As the size of the inter-electrode gap is changed, the applied voltage can be adjusted in order to maintain electrically induced polarization of the filler component.

Abstract: An electric filter comprises a plurality of thin film bulk acoustic resonants (10, 11) arranged in series and in parallel which have electrodes (24, 25) of different working area (L) and optionally a piezoelectric layer (23) of different thickness (T).

Abstract: An electric filter comprises a plurality of thin film bulk acoustic resonators arranged in series and in parallel which have different thicknesses of one or more non-piezoelectric layers, for example top electrode.

Abstract: A ladder-type film bulk acoustic resonator (FBAR) filter comprises two series FBARs and two parallel FBARs. Each FBAR has a top electrode, a bottom electrode, and a piezoelectric layer sandwiched between the top and bottom electrodes. The top electrodes of the two series FBARs form part of a signal line of a coplanar waveguide transmission line. The top electrodes of the two series FBARs are connected to associated circuitry. The two series FBARs have a common bottom electrode.

Abstract: Multiple thin film bulk acoustic resonators (10, 11) configured in series (10) and parallel (11) within a coplanar waveguide line structure provides a compact ladder filter. The resonators (10, 11) are formed over an opening (28) in a substrate (20) and connected to associated circuitry by one or more transmission lines formed on the substrate (20). The arrangement of the resonators (10, 11) between the ground and signal lines of a coplanar line structure provides a means of minimising the area of the filter. Embedding a ladder filter within the coplanar transmission line structure eliminates the need for wire bonds, thus simplifying fabrication. Embodiments for 2×2, and hither order filters are described.

Abstract: A method and apparatus for the spatial distribution of a filler component within the matrix of a composite material are disclosed. An electric field is applied to a mixture consisting of two or more components that have different dielectric permittivities, at least one of which is initially in the form of a liquid polymer or pre-polymer. An alternating electric field is established between a pair of electrical conductors or electrodes that are moved relative to each other, so as to alter the spatial intensity of the electric field in a controlled manner. Polarized particles or elements of the filler component that are coupled to a moving electrode by a dielectrophoretic force can consequently be dragged into a predetermined spatial configuration. As the size of the inter-electrode gap is changed, the applied voltage can be adjusted in order to maintain electrically induced polarization of the filler component.

Abstract: An ultrasonic motor is described which uses radial vibrations of an electro-active material disc (7) amplified by one or more flextensional diaphragms (6) to drive a rotor (4) pressed in frictional contact with the diaphragm (6) by a force imposed by a spring (3) or magentic attraction. The vibrations are converted by elastic fins (5) into rotary motion of the rotor (4). The motor can be operated in any resonant mode that generates vibration at the surface perpendicular to the contact area. Versions of the motor with one or two rotors are disclosed with the two rotor version being used to produce an output in the same direction or opposite directions.

Abstract: A method is provided by which filters consisting of a plurality of think film bulk acoustic resonators (FBAR) fabricated on a semiconductor wafer such as silicon or some other type of wafer can be hermetically packaged in a way that presents a component which can be easily handled by conventional pick-and-place machines. This package consists of a sandwich of the wafer (1) bearing the thin film piezoelectric resonator (2) and at least one silicon wafer (8. 14). The bond between these wafers (1. 8. 14) is accomplished by some means such as anodic bonding, using a low melting point glass or a metal bonding layer. Contacts to the resonating components are accomplished by etching holes (12) through one of the bonded wafers (18) using a process such as deep reactive ion etching. Contact electrodes are deposited into the holes (12) and onto the surface of the wafer bearing the holes (12). The resulting chip components are separated prior to use by sawing or some other method .

Abstract: An electric filter comprises a plurality of thin film bulk acoustic resonants (10, 11) arranged in series and in parallel which have electrodes (24, 25) of different working area (L) and optionally a piezoelectric layer (23) of different thickness (T).

Abstract: An electric filter comprises a plurality of thin film bulk acoustic resonators (10, 11) arranged in series and in parallel which have different thicknesses (T) of one or more non-piezoelectric layers for example top electrode (24).

Abstract: An ultrasonic motor is described which uses radial vibrations of an electro-active material disc (7) amplified by one or more flextensional diaphragms (6) to drive a rotor (4) pressed in frictional contact with the diaphragm (6) by a force imposed by a spring (3) or magentic attraction. The vibrations are converted by elastic fins (5) into rotary motion of the rotor (4). The motor can be operated in any resonant mode that generates vibration at the surface perpendicular to the contact area. Versions of the motor with one or two rotors are disclosed with the two rotor version being used to produce an output in the same direction or opposite directions.

Abstract: The performance of individual detectors in pyroelectric detector arrays is improved by reducing the size of each detector as compared to the overall array size and providing each with a collection cavity which tapers from front aperture towards the detector itself.

Abstract: A method of manufacturing a free standing perovskite lead scandium tantalate film. A film of lead scandium tantalate is formed on a layer of MgO deposited on a sapphire substrate. The MgO layer is etched by phosphoric acid thereby releasing the lead scandium tantalate film from the substrate.

Abstract: A hybrid structure comprising a lens 10, an antenna array 8 and a semiconductor microcircuit 2. The antenna array 8 is formed on a surface of the lens 10 or on a surface of a substrate 14 having substantially the same refractive index as the material of the lens 10. Metal bump bonds 6, 12 provide connections between the antenna array 8 and the semiconductor microcircuit 2.

Abstract: A dielectric bolometer thermal detector of infra-red radiation comprises a layer of dielectric bolometer material, a thermally insulating layer therebelow, a pair of electrodes located on one and the same side of said layer of dielectric bolometer material, a source of bias voltage for providing a bias voltage to said electrode so as to provide a bias field in said layer of bolometer material and a pair of read out contacts respectively connected to said electrodes. A signal which appears between said contacts in response to the application of radiation to said layer of dielectric bolometer material constitutes an output of the detector.

Abstract: A method is described of manufacturing perovskite lead scandium tantalate comprising the pre-reaction of scandium and tantalum oxides at temperatures between 1000.degree. C. and 1400.degree. C. to form scandium tantalate. The scandium tantalate is then reacted with lead oxide to form the desired perovskite phase lead scandium tantalate. In one embodiment there is described a method for the deposition of perovskite lead scandium tantalate films from metal organic precusors. The availability of metal organic precursors allows the deposition of thin films directly from solution or by MOCVD techniques. One particular material, lead scandium tantalate Pb(Sc.sub.0.5 Ta.sub.0.5)O.sub.3, is described. The principal features of the invention are the deposition of scandium and tantalum components from solution or by MOCVD onto the required substrate. These are then prereacted to yield scandium tantalate.

Abstract: Coin validation apparatus having a coin chute including a hard striking surface upon which a coin entering the apparatus is directed. A microphone is positioned to detect acoustic vibrations of the coin after it strikes the striking surface. An output from the microphone is applied to a fast fourier transform device to produce a signal analysis of the coin vibration. A weighbridge measuring apparatus which is made up of a flexible strip of resilient material carried on a support at each end is provided. The coin rolls across the flexible strip to cause a temporary deflection of a center portion of the strip. A strain gauge located at the strip center to produce an electrical signal representative of the deflection. A classifier compares the signal analysis and the strain gauge signal with stored data representative of a set of standard coins, for classifying the coin as a particular coin value.

Abstract: A device for measuring the liquid content of a gas, as for example measuring the liquid water content in the atmosphere. The device employs a probe fabricated in part from a material which is thermally self-stabilizing and which preferably has a positive temperature coefficient. In use the probe is electrically heated and disposed in a flowing gas or is adapted for movement through a static gas so that droplets of liquid are deposited on the surface of the probe. Means is provided for detecting a change in the electrical resistance of the probe in response to a change in the heat loss rate due to the integrated evaporation of droplets of liquid from the surface of the probe. The temperature of the gas, the degree of relative movement between the probe and the gas, and the gas pressure are also sensed so that when their measurements are processed with a measurement dependent on the change in the electrical resistance of the probe a measurement is obtained of the liquid droplet content in the gas.