Abstract: Thin dice of fragile material are formed by making saw cuts in a front surface of a body of fragile material. The saw cuts define the thin dice, and have a depth equal to the desired thickness of the thin dice plus about 1 mil. A support film is then applied to the front surface of the body of fragile material. Using conventional equipment, the back surface of the body of fragile material, opposite the front surface, is ground. The grinding operation reduces the thickness of the body to the desired thickness for the thin dice. Due to the depth of the saw cuts, the grinding process exposes these saw cuts creating the individual thin dice having the desired thickness.

Abstract: An antenna interface unit (AIU) for providing low power loss, fault tolerant connectivity between multiple transmitters and an antenna, and between multiple receivers and the antenna. The antenna interface unit also eliminates single point failures in a transmit/receive (T/R) mechanism. The antenna interface unit includes (a) a power combiner/splitter connectable to the antenna; a receive channel connected to the power combiner/splitter; and a transmit channel connected to the power combiner/splitter. The transmit channel is a different channel from the receive channel. The receivers are connectable to the antenna via the receive channel and through the power combiner/splitter. The transmitters are connectable to the antenna via the transmit channel and through the power combiner/splitter. Different variations of the receive channel and the transmit channel are provided by using different combinations of power combiners and power splitters.

Abstract: Inspection apparatus for determining defects in a planar light transmissive object. A diffuse light is projected through a mask toward an object under test at an inspection location. A digital video camera observes the inspection location and obtains images of the object. These images are examined and processed by a signal processor to obtain indications of various defects. The mask utilized is of a selected design having either multiple alternating narrow clear and opaque stripes, or a single narrow clear stripe straddled by opaque regions or a single narrow opaque stripe straddled by clear regions.

Abstract: A distributed database system includes a plurality of nodes connected via a network medium. Each node runs at least one application and stores a database. Each database at least partially overlaps at least one other database. Each database includes a plurality of tables, and each table includes at least one record. Ownership of each table in the database is assigned to only one application, and only an owning application can modify a table owned by the owning application. Each node also schedules running of the applications on the node such that only one application reads from and writes to the database at a time, distributes updates made to the database to every other database, and updates the database in accordance with received distributed updates.

Abstract: A transformerless power oscillator for driving a high intensity electrodeless light bulb. The driver uses a silicon carbide static induction transistor (SIT) operating as a power oscillator powered by an unregulated power supply potential generated by a full wave rectifier bridge connected to an AC power line. A CW output signal is generated at S-band and is coupled to the excitation coil of an electrodeless lamp by means of a matching network.

Abstract: A hatch assembly having a hatch cover biased to a normally closed position. The hatch cover is connected to an impeller contained and rotatable within a impeller chamber of a housing. When the cover is to be opened, pressurized gas is introduced into the housing causing rotation of the impeller. By virtue of the coupling of the impeller to the hatch cover, the rotation causes the hatch cover to open. After opening, the hatch cover may thereafter be closed by a spring bias forming part of the coupling arrangement.

Abstract: A ceiling arrangement for a high temperature epitaxial growth reactor in which silicon carbide epitaxial layers may be grown. The ceiling includes an upper layer of carbon foam and a lower layer of graphite bonded thereto. A support structure for the ceiling is coupled to a nozzle assembly, holding a gas delivering nozzle. The support structure has a lower flange portion which includes an upwardly extending projection defining a knife edge upon which the ceiling rests. The arrangement minimizes unwanted heat transfer from the ceiling to the nozzle assembly and nozzle.

Abstract: A nitrogen doped single crystal silicon carbide boule is grown by the physical vapor transport process by introducing nitrogen gas into the growth furnace. During the growth process the pressure within the furnace is maintained at a constant value, P.sub.o, where P.sub.o .ltoreq.100 Torr. This is accomplished by measuring the pressure within the furnace and providing the pressure measurement to a process controller which regulates the nitrogen introduction as nitrogen gas is incorporated into the crystal structure. The partial pressure of the nitrogen may be selected to be at a value between 1 and P.sub.o. If the desired partial pressure is less than P.sub.o, an inert gas is added to make up the difference.

Abstract: A silicon carbide metal semiconductor field effect transitor fabricated on silicon carbide substrate with a layer which suppresses surface effects, and method for producing same. The surface-effect-suppressive layer may be formed on exposed portions of the transistor channel and at least a portion of each contact degenerate region. The surface-effect-suppressive layer may be made of undoped silicon carbide or of an insulator, such as silicon dioxide or silicon nitride. If the surface-effect-suppressive layer is made of silicon dioxide, it is preferred that the layer be fabricated of a combination of thermally-grown and chemical vapor deposition deposited silicon dioxide.

Abstract: A heat tolerant, frequency responsive transistor for use in the microwave region includes a collector region, a base region overlying the collector region, and an emitter region including an AlGaN layer overlying at least part of said base region, forming a heterojunction between said base region and said emitter region. The emitter region may include two layers. The HBT may be mounted on a SiC or sapphire substrate. The HBT may include a buffer layer between the substrate and the collector region.

Abstract: A method and apparatus for localizing a point within a sector of a physical surface such as an airport surface that is represented by a plurality of line segments. After entering the physical surface representation, a list of polygons is generated wherein each entry in the list of polygons includes a list of constituent line segments. Then, the list of polygons is organized into a binary tree to encode the relative positions of the polygons. With this organized binary tree, the object can be localized within a polygonal sector by dropping a point representing the object down the binary tree to determine which polygon, if any, encloses the point.

Abstract: A superconducting coil mounted on, and in heat transfer relationship with, a heat conducting support cylinder. The superconducting coil is electrically insulated from the support cylinder by means of a refractory ceramic coating, such as aluminum oxide, on the surface of the cylinder or on an intermediate layer which itself is on the surface of the cylinder. To resist Lorentz forces, the superconducting coil may be positioned within a helical groove machined into the inside or outside surface of the cylinder.

Abstract: The present invention provides for a wet etch and method for preparing a semiconductor device structure from a silicon carbide wafer. A first embodiment of the wet etch comprises a vessel, a tetrahydrofurfuryl alcohol and potassium nitrite etching solution within the vessel, an electrode, a wafer support for positioning at least a portion of the silicon carbide wafer within the etching solution, and a voltage source coupled with the electrode and the wafer support. A second embodiment of the wet etch comprises a wafer carrier for holding at least one wafer, a polishing plate adjacent the wafer carrier, a voltage source having a first terminal electrically coupled with the wafer and a second terminal electrically coupled with the polishing plate, and an applicator adjacent the polishing plate for depositing an etching solution on a surface of the polishing plate.

Abstract: A switch having spaced apart conductors with a high resistivity gate member therebetween. First and second mercury droplets are respectively connected to the ends of the conductors. When a control signal is applied to the gate member, the mercury droplets are drawn to it and establish electrical connection between the conductors to close the switch. Upon removal of the control signal the mercury droplets separate and assume their initial droplet form thus opening the switch.

Abstract: A programmable digital radio is configured to perform navigation functions. A receiver in the programmable digital radio receives analog signals from a navigation unit and digitizes the analog signals to produce digital navigation signals. The digital navigation signals are processed digitally and valid navigation information is determined. Processing includes generation of baseband signals including in-phase signals and quadrature signals, AM demodulation, filtering, decimating, demultiplexing, discrete fourier transformation, and function processing according to a selected function. The selected functions may include Localizer, Marker Beacon and Glideslope.

Abstract: A winch 100 is provided for taking up or paying out cable 13 without damaging protrusions 14 spaced along the cable from potentially high compressive forces applied to the cable when it is wound over drum members 16, 18, 20 of each of a pair of drum mechanisms 30A and 30B. The winch is operated so that the cable is pulled over the drum members and wound about the two drum mechanisms as a unit, such that successive cable protrusions are always maintained in successive cable path spaces between the drums of each drum mechanism.

Abstract: A static induction transistor having a silicon carbide substrate upon which is deposited a silicon carbide layer arrangement. The layer arrangement has a plurality of spaced gate regions for controlling current flow from a source region to a drain region vertically spaced from the source region by a drift layer. The pitch distance p between gate regions is 1 to 5 microns and the drift layer thickness d is also 1 to 5 microns.In one embodiment the source regions are positioned alternatively with the gate regions and are formed in a top layer of high doping concentration. In another embodiment the gate regions are ion implanted in the layer arrangement.In another embodiment the structure includes a dual oxide layer covering gate and source or drain regions, and in yet another embodiment contacts for the drain, source and gate regions are located on the same side of the substrate member.

Abstract: A closed loop liquid cooling system for an RF transistor module including a plurality of elongated microchannels connected between a pair of coolant manifolds for conducting liquid coolant beneath one or more transistor dies to dissipate the heat generated thereby, a heat exchanger, a miniature circulating pump located on the module, and passive check valves having tapered passages for controlling the flow of coolant in the loop. The valves are truncated tapered passage microchannel valves having no moving parts and are fabricated so as to be a part of either the circulating pump, the coolant manifolds, or the microchannels.

Abstract: A capacitor module having a solid dielectric is cleared in a gaseous environment having an electric strength greater than that of air at a pressure of one atmosphere. A plurality of such cleared capacitor modules is formed into a stack which itself is then cleared by the same clearing process. During intended operation in an electric circuit, the capacitor arrangement would be maintained in such gaseous environment having an electric strength greater than that of air at a pressure of one atmosphere.

Abstract: An array of individual and autonomous modules are deployed in a region to be surveilled. Each module, contained in an air dropable bomblet, includes a GPS system for determining the exact location of the deployed module. The module also includes an rf receiver and transmitter, as well as an atomic clock circuit for providing highly precise time and clocking signals, with operation of the module circuitry being governed by a control computer. The computers of the modules are individually programmed such that the modules of the array collectively operate as a distributed phased array antenna system, but without any hardwired interconnection between the modules. In another embodiment a single receiver is utilized and the apparatus operates on the frequency set of the GPS system.