Abstract: Quartz cuts are provided which exhibit temperature characteristics which are favorable for making differential SAW temperature sensors. Families of Y cuts rotated between 0° and 60° degrees in combination with placement of two resonators at specified angles to each other are disclosed. Further, preferred embodiments in which the resonators are placed on opposite sides of a zero TCF line are disclosed, to provide wide temperature differences while efficiently utilizing the available bandwidth. The design permits placement of the resonator at angles smaller than 12.5° and even less than 5° therebetween, most preferably on quartz rotated Y cut between 28.5° and 42.75°.

Abstract: Quartz cuts are provided which exhibit temperature characteristics which are favorable for making differential SAW temperature sensors. Families of Y cuts rotated between 0° and 60° degrees in combination with placement of two resonators at specified angles to each other are disclosed. Further, preferred embodiments in which the resonators are placed on opposite sides of a zero TCF line are disclosed, to provide wide temperature differences while efficiently utilizing the available bandwidth. The design permits placement of the resonator at angles smaller than 12.5° and even less than 5° therebetween, most preferably on quartz rotated Y cut between 28.5° and 42.75°.

Abstract: A split ring coupler having a stator ring having at least one split in it such that the stator has at least a first and a second end and a rotor ring having at least one split in it such that the rotor ring has at least a first and a second end, said rotor ring being oriented substantially coaxially with and axially spaced apart from said stator ring. At least one SAW resonator is electrically coupled between said first and second ends of the rotor ring in series therewith, neither of said ends of said stator ring being directly connected to ground.

Abstract: The present invention relates to a method and apparatus for assessing the condition of a wheel particularly, but not exclusively, to a method and apparatus for assessing the condition of a tire rotating on a vehicle wheel. Apparatus is provided comprising a plurality of antennas (101, 102, 103, 104, 105, 106, 107, 108) for transmitting an interrogation signal to a sensor (110, 112), the sensor being mounted to a wheel to be assessed and being adapted to detect the condition of the wheel; wherein the antennas are arranged in a line along a path to be followed by a wheel to be assessed.

Abstract: A pressure monitor has a base and a lid secured to the base to define a substantially fluid tight chamber. At least part of the lid is flexible and forms a diaphragm which deflects responsive to changes in fluid pressure surrounding the monitor. A projection provided on the diaphragm transmits movement thereof to a distortable substrate located within the chamber. A first SAW device is mounted on the distortable substrate, and at least a second and third SAW device are mounted within the chamber. The second SAW device carried on a reference substrate section has its direction of propagation inclined at an angle to the direction of propagation of at least one of the first and third SAW devices. This way movement of the diaphragm induced by a change in pressure in the zone surrounding the monitor results in distortion of the distortable substrate, which is measurable by the SAW device mounted thereon, without distorting said reference substrate section.

Abstract: A system for interrogating a tire sensor. The disclosure provides a wheel (2) including a sensor (14) and an electrical conductor (18, 20) extending about a rotational axis (4) of the wheel (2), the sensor (14) being electrically coupled to said electrical conductor (18, 20). Communication between the sensor and a remote interrogating apparatus is thereby improved.

Abstract: An arrangement for tracking resonant frequency of electrically resonant structures through a single channel includes a variable frequency oscillator associated with each resonant structure which provides an excitation signal of a variable frequency encompassing a possible resonant frequency of the associated resonant structure. Coupling device(s) are provided which connect each variable frequency oscillator to said resonant structure(s). An I-mixer is provided for each oscillator which forms a synchronous detector, a first input of each I-mixer being connected to its associated oscillator and a second input being connected to the coupling device, each I-mixer mixing the excitation signal from the associated variable frequency oscillator with a response signal generated by the resonant structure(s) in response to each excitation signal.

Abstract: A surface acoustic wave (SAW) sensor includes a transducer (240 provided on a substrate (23), wherein the transducer (24) is oriented on the substrate (23) so that the direction of acoustic wave propagation is such that the variation of sensor output with temperature, associated with the variation of the substrate third-elastic constants with temperature, substantially equal but opposite to the sum total of the variation of sensor output with temperature associated with the substrate linear temperature coefficient of expansion and with the variations with temperature of the substrate non-zero third order elastic constants, the substrate first-order elastic constants and the substrate density. The effect of temperature variation on sensor output is thereby minimized. This is achieved with a 35-degree arrangement or with reflective gratings inclined at an angle of 3.1 degrees to normal. Additionally, a robust package with a dish is given. Particular applications include the measurement of torque.

Abstract: A method of mechano-chemical fluorination is described that has a significantly improved yield over prior art methods of synthesis. The present invention illustrates this improved mechano-chemical Fluorination by describing the improved synthesis of Fullerene Fluorides (FF). This method overcomes reduced product yield that results from vibromill material corrosion. This method also overcomes the prior fluorination and FF synthesis problems of the prior art by utilizing different fluorinating materials, adding catalysts and diluting agents to the process, varying milling times, and heating in the presence of inert gasses to improve the fluorination process.