Abstract: A gate turn-off thyristor includes a substrate formed of n-type silicon carbide; a growth buffer formed of n-type silicon carbide and positioned to overlie said substrate; a field buffer region formed of p-type silicon carbide and positioned to overlie said growth buffer; a drift region formed of p-type silicon carbide and positioned to overlie said field buffer region; a gated base region formed of n-type silicon carbide and positioned to overlie said drift region; a modified anode region formed of first, second and third layers of silicon carbide and positioned to overlie said gated base region, said first layer comprising p-type silicon carbide and disposed adjacent said gated base region, said second layer comprising n-type silicon carbide and disposed adjacent said first layer, said third layer comprising p-type silicon carbide and disposed adjacent said second layer; an anode contact disposed on said third layer of said modified anode region; a cathode contact disposed on said substrate; and a gate cont

Abstract: An interband cascade (IC) light emitting device having narrow ridges, and a method of growing and fabricating the IC light emitting device is disclosed. The IC light emitting device produced by the method of the present invention has 18 active regions separated by n-type injection regions and a plurality of coupled quantum wells of Al(In)Sb, InAs, and Ga(In)Sb layers. The IC light emitting device produced according to the present method has a differential external quantum efficiency of at least 500%, a peak power output of at least 4W/facet, a power conversion efficiency of at least 14% in continuous wave at 80K, a power conversion efficiency of at least 18% in pulsed wave operation at 80K, a continuous wave operation temperature of 142 K or less, a thermal resistance of from about 24-29 K*cm2/kW and continuous wave output powers of at least 100 mW/facet at temperatures above 77K.

Abstract: A magnetic sensing device that senses low frequency magnetic fields by using movable flux concentrators that modulate the observed low frequency signal. The concentrator oscillates at a modulation frequency much greater than the observed magnetic field being sensed by the device. The modulation shifts this observed signal to higher frequencies and thus minimizes 1/f-type noise. This is preferably accomplished by the oscillatory motion of a microelectromechanical (MEMS)—type magnetic flux concentrator operated with a magnetic sensor, preferably made on a common substrate. Such a combined device can be used in a magnetometer. Such a device is small, low-cost and has low-power-consumption requirements. The magnetic sensor can be a Hall effect or other type of magnetic sensor. At least one modulating flux concentrator is used with the magnetic sensor.

Abstract: A system which derives the attitude of a body as it rotates and travels through the earth's magnetic field. At least one magnetometer is placed in the body and provides an output signal during flight of the body. The zero crossings of the output signal are used to formulate a time discriminant. This time discriminant is compared with a roll angle discriminant for which a value of attitude has been previously determined. From the comparison, the attitude during flight may be determined. A time discriminant can also be formulated using two magnetometers.

Abstract: A terahertz electromagnetic energy detector comprises a (100) oriented multiple quantum well thermally bonded to a first transparent substrate having a direction dependent thermal coefficient of expansion such that this coefficient matches the thermal coefficient of expansion of MQW in one direction but different form the direction-dependent thermal coefficient of expansion of the MQW in a perpendicular direction. The resultant internal thermally induced anisotropic strain leads to a polarization dependence of the optical absorption that is strongest near the lowest heavy-hole and light-hole exciton peaks. A second transparent substrate is placed beneath the first transparent substrate and is oriented so that its thermal coefficients of expansion act in a direction perpendicular to those of the first transparent substrate so that the accumulated phase retardation of the optical wave associated with birefringence of the substrate is effectively cancelled.

Abstract: A Silicon Carbide (SiC) Gate Turn-Off (GTO) thyristor is formed of a substrate having at least three epi-layers provided thereon as first, second and third doped regions, respectively, and the substrate being a fourth doped region, wherein the at least four doped regions alternate between a p-type doping and an n-type doping, with the regions being at least partially overlaid. An anode is arranged on the first region, and a base is arranged on the second region. A controlling gate is arranged on the third region, and a cathode is arranged on the fourth region. A current divider divides the load current between the anode and the base. This reduces the voltage drop of a portion of the load current passing through the thyristor, allowing for the switching of higher current densities than in prior art thyristors, faster switching speeds and reduced junction temperatures.

Abstract: A low cost protective cap that will offer protection of deployable fins for full bore artillery projectiles. A form fitting, composite cap that disintegrates on muzzle exit acts as a protective measure. The cap interfaces with the projectile obturator to form a temporary seal against hot gun gasses. The composition and thickness of the cap allows gas infiltration into the cap material and essentially instant cap degradation upon shot exit.

Abstract: A beamsplitter prism for transmitting and reflecting spherical waves without magnification, which includes at least first and second surfaces arranged opposite each other; a semi-reflecting layer diagonally arranged from a lower portion of the first surface to an upper portion of the second surface. The first and second surfaces are adapted to have a spherical shape, with the first surface having a smaller radius than the second surface to form two concentric spheres. A spherical wave which strikes the first surface will pass through the semi-reflecting layer and exit through the second surface without having the beamsplitter prism introduce distortion to the wave. The second surface may be substantially orthogonal to the first surface, so that a spherical wave may reflect off the semi-reflecting layer and exit through a spherical surface. A third planar surface may be arranged on the prism to permit the passage of plane waves without distortion.

Abstract: An apparatus for monitoring the cure of a resin-impregnated material includes a pultrusion die; a plurality of first electrodes mounted in the pultrusion die; a plurality of insulators surrounding the plurality of first electrodes, respectively, in the pultrusion die; a resin-impregnated preform that includes a second electrode therein, the resin-impregnated preform being inserted into the pultrusion die; a constant contact electrode that contacts the second electrode; and a power supply connected to the constant contact electrode wherein electric current flows from the power supply to the constant contact electrode then to the second electrode then through the resin-impregnated preform to the plurality of first electrodes.

Abstract: A single particle photoacoustic absorption spectrometer for directly measuring the absorption spectra for in situ individual aerosol type particles that is comprised of an electrodynamic trap capable of suspending a charged particle in free-space in a non-intrusive manner; a source of modulated monochromatic electromagnetic radiation, e.g., a laser, and an acoustic transducer/resonator for detecting/amplifying sound waves emitted by the irradiated particle. Depending on the characteristics of the particle, a certain fraction of the electromagnetic energy will be absorbed by the particle resulting in its rapid heating and cooling at the modulation frequency. The heat generated within the particle is rapidly transferred to the surrounding air resulting in a sound wave. The intensity of the sound wave is proportional the absorbed energy by the particle.

Abstract: A polarization-sensitive infrared (IR) detector array for use in infrared cameras and other IR based instruments, is comprised of multiple corrugated quantum well infrared photodetector elements (C-QWIP) that form a unitary detector unit (cell). The array is preferably two-dimensional, which can detect polarization contrast of an observed object in a scene. Each detector unit (cell) is formed by a group of C-QWIP detector elements having different groove orientations and cross sections. Each detector unit (cell) has at least two C-QWIP detector elements with their respective corrugations orthogonally oriented. Infrared detection by these detector cells is primarily by polarization contrast, compared to intensity contrast, which is well known in the art. By measuring polarization of reflected light from the observed object, the type of material can also be identified. A first array embodiment of the invention comprises four C-QWIP elements that form a cell.

Abstract: A beamsplitter prism for transmitting and reflecting cylindrical waves without magnification, which includes at least first and second surfaces arranged opposite each other; a semi-reflecting layer diagonally arranged from a lower portion of the first surface to an upper portion of the second surface. The first and second surfaces are adapted to have a cylindrical shape, with the first surface having a smaller radius than the second surface to form two concentric cylinders. A cylindrical wave which strikes the first surface will pass through the semi-reflecting layer and exit through the second surface without having the beamsplitter prism introduce distortion to the wave. The second surface may be substantially orthogonal to the first surface, so that a cylindrical wave may reflect off the semi-reflecting layer and exit through a cylindrical surface. A third planar surface may be arranged on the prism to permit the passage of plane waves without distortion.

Abstract: A device for generating and radiating pulses of radio frequency/microwave energy in response to pulses of laser light in which a metal layer is ohmically bonded to each side of a substrate of semiconductior material and an antenna bowtie pattern is ohmically bonded to the metal layers to form a feed structure for a Luneburg lens type antenna. There is at least one aperture available on the substrate of the semiconductor material for permitting laser light to reach the disk to produce photoconduction. The photoconductive switch is electrically connected to the storage device to facilitate fast discharge of the stored energy through the switch. The feed structure is mounted on a motorized support stand, which is connected to a center post by an arm that can rotate 360° in the azimuthal direction and ±90° in elevation. The feed structure is located on the outermost shell of the Luneburg lens, and is concave to conform to the focal radius of curvature of the outermost shell.

Abstract: A method of forming fiber reinforced polymer matrix composite structures having a low volume fraction of fiber reinforcement and carefully controlled thicknesses is provided. The method enables the production of composite structures having a fiber volume fraction of less than about 0.5 through the use of vacuum bag molding, thereby eliminating the need for expensive closed molds, The method also eliminates the occurrence of “racetracking” of uncured resin during the resin infusion process.

Abstract: An electronic safe and arm apparatus disposed in a projectile having a spin axis and a spin rate includes a battery; a power supply board connected to the battery, the power supply board including a mechanical G-switch that closes permanently at a predetermined acceleration, and a time-delay circuit connected to the G-switch; a firing board connected to the power supply board, the firing board including: an accelerometer that is oriented perpendicular to and disposed a fixed distance from the spin axis, an output of the accelerometer varying according to the fixed distance from the spin axis and the spin rate of the projectile; a comparator connected to the output of the accelerometer wherein the comparator compares the output of the accelerometer to a threshold voltage and an output of the comparator is low when the output of the accelerometer is less than the threshold voltage and the output of the comparator is high when the output of the accelerometer exceeds the threshold voltage; a rectifier connected t

Abstract: A method to determine the direction in which a spinning projectile is traveling. A solar sensor array on the projectile is used to calculate the orientation of the axis of rotation of the projectile with respect to a known solar field and a magnetometer sensor array is used to calculate the orientation of the axis of rotation of the projectile with respect to a known magnetic field, both fields being represented by respective vectors having magnitude and direction. With the known and calculated orientations, the pointing direction may be obtained by vector combination.

Abstract: A hardened subminiature telemetry and sensor system for a ballistic projectile having a radome, antenna, steel insert, S-band transmitter circuit board, data recorder, sensor or measurement device and battery. The entire assembly is contained in such a way that the assembly can be threaded into the existing tracer well of a kinetic energy projectile.

Abstract: A built-in test system for analog or mixed signal circuits comprises a discretizer for discretizing analog test signals monitored at various node points of the circuit under test into suitable discrete values. The discrete values are compared with a reference signature in an analog signature generator to determine if a fault is likely. Since analog signature generators use multilevel data, the computations are performed in Galois field GF(p), where p is the radix. The analog signature generator is constructed using current-mode shift registers, signal discretizers, signal level shifters, mod-p adders, subtractors and multipliers.

Abstract: A method of producing multilayered conformal coatings of tunable, low electronic loss ceramic composites is carried out by mixing two-phase BSTO/MgO into a base solution of typical lab grade acetone to form a mixed solution, inserting two platinum sheets separated into the mixed solution, applying a constant direct current (DC) bias across the two platinum sheets acting as electrodes, and stirring to reduce sedimentation of particles using a magnetic stirrer. Deposition is also performed on insulating substrates by initially coating them with conducting films of Au, performing BSTO deposition, and subsequently sintering the dielectric film so that the underlying metal film evaporates.

Abstract: A frequency-scan traveling wave antenna receives radio frequency (RF) energy at an input port, passes the energy through a quarter wave transformer to a first radiator element in an array of radiator elements, each pair of radiator elements being connected by a respective delay line. Each radiator element includes an input port of known characteristic impedance connected to an impedance matching section which compensates for that element's radiated power. Each radiator element has an output port with a section of transmission line disposed between a main radiator section of said radiator element and said output port, and impedance matched to the output port. In one embodiment, each delay line includes a plurality of delay line sections, with adjacent delay line sections being mutually perpendicular. In a second embodiment, each delay line includes a plurality of delay line sections disposed in meandering form.