Abstract: An antenna with first and second spaced radiating elements extending from a vertex at respective first ends and diverging from each other in a direction outward from the vertex to respective second ends. Each radiating element second end is connected to a first end of a terminating element through a coupler. The second end of each terminating element is connected to a common ground plane.

Abstract: An overvoltage circuit detects differences between the supply voltage from a first circuit and the operating voltage of a second circuit. The circuit may detect when the power supply value of the first circuit is below, above, or equal to the operating voltage of the second circuit. The overvoltage circuit consumes substantially zero static current and may be used in a variety of implementations.

Abstract: A three axis rate sensor includes a substantially planar vibratory resonator having a substantially ring or hoop-like structure with inner and outer peripheries extending around a common axis, drive means for causing the resonator to vibrate in a Cos 2? vibration mode, carrier mode pick-off means for sensing movement of the resonator in response to the applied drive z-axis response mode, pick-off means for detecting movement of the resonator in response to rotation about the z-axis, z-axis response mode drive means for nulling said motion, x-axis response mode pick-off mean for detecting movement of the resonator in response to rotation about the x-axis, x-axis response mode drive means for nulling said motion, y-axis response mode pick-off mean for detecting movement of the resonator in response to rotation about the y-axis, y-axis response mode drive means for nulling said motion, and support means for flexibly supporting the resonator and for allowing the resonator to vibrate relative to the support means

Abstract: A procedure for temporally isolating an environmentally dependent integrated circuit fault includes the steps of determining a marginally failing and a minimally passing environmental condition corresponding to the fault; identifying a clock cycle Tmax at which the fault was first detected; determining a candidate clock cycle at which the fault may have occurred; and iteratively a) applying test pattern subsets from an initial clock cycle through the candidate clock cycle under the marginally failing environmental condition; b) applying remaining test patterns under the minimally passing environmental condition; and c) adjusting the candidate clock cycle based upon whether the fault occurred during test pattern subset application up through the candidate clock cycle under the marginally failing environmental condition. Candidate clock cycle adjustment in accordance with a binary search technique enables determination of an exact clock cycle at which the fault occurred in a maximum of Log2 (Tmax+1) iterations.

Abstract: A gapless Vivaldi notch/meander line antenna is provided having a top plate with a Vivaldi notch, a cavity and a rearwardly-extending notch, with the top plate having integral side plates and a meander line bridging the rearwardly-extending notch at its distal end.

Abstract: This invention relates to a switching circuit, such as a bridge circuit, comprising first and second switches operable to produce an electrical signal at the output of the switching circuit at certain voltages. Moreover, this invention also relates to a method of operating such a switching circuit. The switching circuit comprises an input operable to receive a DC signal of +Vs, an output, first and second switches operable in response to first and second switching signals to be switched between on and off states such that switching between various combinations of on and off states produces an electrical signal at the output with voltage pulses at levels of +Vs, 0V and ?VS and a voltage sensor for producing a signal indicative of a voltage offset in the switching circuit. Voltage effects in the switching circuit can be compensated for by using the signal produced by the voltage sensor.

Abstract: Offset correction methods and apparatus for a focal plane array. A bolometer array configured in a row and column readout format has dedicated column circuits to measure the resistance of each bolometer in the column. A high speed on-chip analog to digital converter converts the analog sensor signal to a digital representation. Various offset control methods and apparatus are employed to correct the digital representation for variations in individual bolometer response that are not necessarily associated with signals of interest.

Abstract: A rotating machine including a rotating shaft: a plurality of conductive rotor bars spaced from the rotating shaft and fixed to the rotating shaft through at least one intermediate member, where at least one of the plurality of conductive rotor bars have at least one first internal conduit; and a circulator for establishing a coolant circulation through the first internal conduit.

Abstract: A technique is provided that uses a dual mode seeker (IR and LADAR) for precise target dynamics measurement, which extends stripping to a much higher altitude than ground based radar. Initial results show that this approach works to altitudes in excess of 100 km. Stripping becomes a reliable way to discriminate lighter weight decoys from reentry vehicles at altitudes and ranges consistent with planned divert capabilities for terminal phase missile defense. It is a finding of this invention that the LADAR will improve the spatial resolution by a factor of five over typical missile defense IR seekers using a common aperture. The LADAR provides a 3D angle, angle, range (AAR) image for each laser pulse which is used to extract the precise target state vectors.

Abstract: A semiconductor-based, photo detector device capable of simultaneously detecting two or more selected wavelengths of light on a pixel-registered basis. The device has detector layers of selected semiconductor materials of one micron or less in thickness interspersed with contact layers, each detector layer having a different light absorption to wavelength response curve. All contact layers, including detector bias voltages, have electrical contacts on the backside of the pixel for discrete pixel connection to mating connections on a suitable ROIC substrate. Among its several embodiments, there is a multi-color detector array and a single channel per pixel differential optical signal detector.

Abstract: An antenna system, to enable communication with a moving vehicle via a satellite, utilizes an array of subarrays contiguously positioned in a diamond-type pattern. Straight edge boundaries of an array can maximize sidelobe degradation resulting from diffraction effects at the edge. The diamond-type array pattern provides saw tooth array edge boundaries with all edge portions at 45 degrees (or other suitable acute angle) to the principal array dimension (the length dimension). Uniform excitation may be provided for all subarrays via a binomial power divider/combiner configuration. Mechanical beam steering can be provided in azimuth and elevation. A phase shifter assembly may be provided to enable a limited electronic scan (e.g., plus or minus 2 degrees) to increase beam steering agility from a moving vehicle. Thin flat-plate subarray design details are provided.

Abstract: A system for launching, refuelling and recovering in flight an aircraft (10) such as an unmanned aerial vehicle (UAV) from a larger carrier aircraft (16) comprising a holder (22) on the carrier aircraft (16) to which the UAV (10) is detachably connectable and an extendable and retractable refuelling device (23, 24) on the carrier aircraft (16) detachably connectable to the UAV (10) whereby to launch the UAV it is disconnected from the holder (22), the refuelling device (23, 24) is extended with the UAV connected thereto to cause the UAV to trail behind the carrier aircraft and the UAV is then disconnected from the refuelling device.

Abstract: A single dual mode monolithic focal plane array having an active sensor and a passive sensing capability is switched from one mode to the other by switching the bias across the cells of the array from a passive IR mode to an active LADAR mode, with the monolithic dual mode focal plane array having applications in missile target seekers and laser target designators. The switching is accomplished by increasing the gain of the array by as much as 30 times that associated with IR detection when laser return pulses are expected. Thus, there need be no mechanical changes to the array to afford both passive IR sensing and an active LADAR pulse detector. Nor need there be two different focal plane arrays, one for IR and one for laser radiation, which leads to boresighted alignment problems.

Abstract: The present invention features an RF-actuated microelectromechanical systems (MEMS) switch for use with switchable RF structures such as antennas. An antenna within each MEMS switch module is coupled to a tuned circuit and a detector. The DC voltage output of the detector is used as the control input to the MEMS switch. This allows arrays of MEMS switch modules to be actuated by remotely generated radio frequency signals thus alleviating the need for running metallic conductors or optical fibers to each MEMS switch. The MEMS switch is particularly suited for use in conjunction with both passive and active antenna elements to allow reconfiguration of antenna or other RF structures. Frequency response characteristics, phasing, and directionality characteristics may be altered easily.

Abstract: For those optical waveguides that require the deposition of a thick film and a high-temperature anneal to create an appropriate waveguide medium, wafer warping, bowing or dishing is reduced or eliminated by depositing a film of the same thickness on the backside of the wafer so as to relieve film stress during the deposition and annealing process. In one embodiment the waveguide medium is silicon oxynitride, although other depositable thick films may be utilized in place of the silicon oxynitride.

Abstract: An apparatus and method for detecting gases, gasified agents or other analytes. The apparatus includes a solid body having a first surface area and a second surface area. A first, preferably polymeric, coating is superimposed on the first surface area of the solid body. A second, preferably polymeric, coating is superimposed on the second surface area of this solid body. The first coating and the second coating are different materials which adsorb different agents at different rates. A wave propagating transducer is positioned adjacent the solid body to propagate a first wavefront adjacent the first surface area of the solid body. This wave propagating transducer also propagates a second wavefront adjacent the second surface area of the solid body. These first and second wavefronts interfere to produce an interference pattern which is unique to the particular agent which is adsorbed by the first and second coatings.

Abstract: A system is provided for nulling out or eliminating alignment errors in an optical system by moving a lens to capture and center a collimated beam laterally-shifted by thermal excursions, thus to couteract the boresight error caused by the thermally-induced lateral shifting. As a result, alignment error the thermal coefficient of expansion characteristics of the optical elements and their mounting systems caused by lateral off-sets is corrected by moving a lens or lens system in response to thermal changes in a direction which moves the lens so that the collimated light impinging on the lens is made to come in on the optical axis of the lens.

Abstract: Methods for navigating a remote controlled vehicle, methods for maintaining a formation of remote controlled vehicles, and remote controlled vehicles using those methods. A vehicle is navigated using the Global Positioning System (GPS). Upon dropout of the GPS, the vehicle is navigated using a laser tracking system and one or both of: (i) a compass and (ii) wheel encoders. The navigation system may be used, in one embodiment, to maintain an echelon formation of remote controlled mine detection vehicles.

Abstract: In one embodiment, an AC ground fault detector system senses an AC signal indicative of an unintended electrical path between a load driven by a power source and a reference potential using a capacitively coupled circuit.

Abstract: A meander line loaded antenna is provided with a ferrite donut surrounding a portion of the meander line so as to effectively lower the operating range of the meander line loaded antenna by as much as 30%. At the lower frequencies the ferrite material introduces a minimal loss of 2 to 3 dB, whereas at the higher frequency range very little current passes through the meander line thus eliminating any effect of the ferrite on antenna performance. The utilization of the ferrite surrounding a meander line element permits the use of the miniaturized antenna and size for size reduces the low frequency cut off of the antenna.