Abstract: A system for providing a user with situational information. A user state is defined by information specific to a user, such as location and physiological state of the user, (e.g. fatigue). A travel state is defined by information regarding a transportation service, for example delayed or on time. A geo-location state is determined by the user's location. Situational information is displayed to the user based on the user state, the travel state, and any relevant merchants that are nearby the user. This may include information about the transportation, merchants, or advertisements. The user state may also include sensor data from at least one wearable sensor located on the user. The user state may be aggregated from multiple users to determine congestion, predict emergency situations, and provide alternative routes.

Abstract: A photon triggered RF radiator having separate sections to perform the eny storage and the energy radiation functions. The energy storage function is performed by at least one charging electrode positioned on the upper surface of a photoconductive dielectric substrate, whereas the energy radiation function is performed by a charging electrode positioned adjacent to the charging electrode on the upper surface of the substrate. The charging electrode and the radiating electrode are separated by a predetermined gap distance that is large enough to insure there is no surface flashover between the electrodes and small enough to insure the efficiency of energy discharge from the charging pad to the spiral antenna is maximized.

Abstract: A monolithic photoconductive pulsar utilizing a radial transmission line structure to store energy and a unique optical pulse illumination means to trigger the radial transmission line to radiate extremely, high voltage gain, narrow bipolar pulses. By achieving a higher voltage gain, the bipolar RF pulses are desirable in that they substantially improve the efficiency and lifetime of the device over the prior art.

Abstract: A photoconductive switch coupled to an energy storage device wherein the tch is comprised of photoconductive semiconductor material while the energy storage device comprises two spiral metalized arms that make up a spiral antenna. The photoconductive switch is electrically connected to the storage device to facilitate fast discharge of the stored energy through a load. A variation comprises a storage device comprising two separate pieces of substrate material each having a spiral metalized arm. The separate pieces being connected by highly dielectric material to form a spiral antenna ultra wideband radiator.

Abstract: A photoconductive ultra-wideband impulse generating device utilizing pulse harpening techniques to further increase its radiation frequency well above the gigahertz range while also substantially improving radiation efficiency. Such pulse sharpening provides for a radiator having a wider range of applications.

Abstract: An electronically controlled frequency agile impulse source utilizing pulse sharpening techniques to increase its versatility in radiating impulse energy at a variety of center frequencies and bandwidths in the megahertz to the gigahertz range. Such pulse sharpening provides for a radiator having a wider range of applications.

Abstract: A photoconductive switch coupled to an energy storage device wherein the tch is comprised of photoconductive semiconductor material while the energy storage device comprises two discrete dielectric mediums. Each medium having a conductive electrode on the top and bottom surfaces to essentially form parallel capacitors wherein the parallel capacitors are separated by a predetermined gap distance. A photoconductive switch electrically connected to each medium such that the switches are located on the opposite sides of their respective mediums. The predetermined gap distance (between the electrodes) and the photoconductive switches (on opposite sides of the storage devices) provide suppression of surface flashover between very high voltage, charged electrodes. Such flashover suppression allowing for very high power pulse generation.

Abstract: The combination of a photoconductive switch coupled to an energy storage ice wherein the switch is comprised of photoconductive semiconductor switch while the energy storage device comprises a tapered radio transmission line. A photoconductive semiconductor gallium arsenide switch is embedded in a circular disc of dielectric material having a thickness dimension which reduces linearly outward from the center, with upper and lower layers of continuous radial metallization configured in a circular pattern located thereon. The upper layer of metallization includes an apertured grid adjacent one surface of the switch, while the outer conductor of a coaxial output signal line is connected to the metallization layer on the opposite side with the inner conductor thereof passing through the dielectric layer to the undersurface of the semiconductor switch.

Abstract: Bulk gallium arsenide having a high hold-off voltage is optically activated by a laser resulting in high power output. A high voltage input is applied to a semi-insulating gallium arsenide material. The gallium arsenide material is activated by laser light, thereby resulting in large current conduction. An external oscillating signal is superimposed on the high current resulting in a high power output.

Abstract: A device for generating pulses of radio frequency energy in response to pulses of laser light in which a circular wafer of GaAs has metallized annular layers ohmically bonded to the wafer by epitaxial GaAs layers, and an epitaxial layer of AlGaAs in the center of one of the annular epitaxial layers through which laser light is to be directed, there being a plurality of apertures in the metallized layer in contact with the AlGaAs epitaxial layer. In addition, an AlGaAs epitaxial layer may be formed opposite the first AlGaAs layer and an optical fiber is brought into contact with it so that laser light can be introduced at both sides of the wafer.

Abstract: A photoconductive switch coupled to an energy storage device wherein the tch is comprised of photoconductive semiconductor material while the energy storage device comprises two quasi-radial transmission line including a different material, i.e. a dielectric storage medium. The photoconductive semiconductor gallium arsenide switch is electrically connected to two quasi-radial transmission lines formed in part by layers of metallization configured in a quasi-radially shaped pattern upon the energy storage device. A variation comprises a photoconductive semiconductor gallium arsenide wafer sandwiched between two quasi-radial transmission lines so that the semiconductor gallium arsenide wafer serves as substrate, energy storage medium, and photoconductive switch.

Abstract: A high voltage sub-nanosecond pulser and radiator including a radial transsion line consisting of a dielectric member sandwiched between two patterned layers of metallization, one of which comprises a plurality of radiating elements. A photoconductive semiconductor gallium arsenide switch is embedded in the dielectric member which has a constant thickness. The other layer of metallization includes an apertured grid adjacent one surface of the switch for application of an energization pulse of laser light.

Abstract: The combination of a photoconductive switch coupled to an energy storage ice wherein the switch is comprised of photoconductive semiconductor material while the energy storage device comprises a radio transmission line including a different material, i.e. a dielectric storage medium. A photoconductive semiconductor gallium arsenide switch is embedded in a circular disc of dielectric material with upper and lower layers of continuous radial metallization configured in a circular pattern located thereon. The upper layer of metallization includes an apertured grid adjacent one surface of the switch, while the outer conductor of a coaxial output signal line is connected to the metallization layer on the opposite side with the inner conductor thereof passing through the dielectric layer to the undersurface of the semiconductor switch.

Abstract: An optically activated avalanche GaAs switch having two opposing optical windows for receiving optical energy from an illumination source which may be, for example, a laser diode operating at a 1.06 micron wavelength. The switch is a semiconductor PIN structure including a substrate of intrinsic GaAs material within which is formed opposing highly doped deep recessed p+ and n+GaAs layers underlying a pair of ohmic contacts including outer annular layers of metallization which surround respective centrally located optical windows formed of AlGaAs. By illuminating the switch from opposite sides through the optical windows, electron-hole pairs are generated and a condition for an avalanche mode of operation is created in the center region of the device rendering it conductive.

Abstract: A photoconductive switch with a low threshold energy, high voltage capability and fast rise time consisting of a semiconductive substrate comprised primarily of gallium arsenide, patterned electrodes masked onto the substrate on opposite sides, a power supply and a laser that introduces laser light via fiber optic bundles to the substrate and parallel to the applied electric field.

Abstract: A pulse forming network with distributed inductance and capacitance is diosed for use in a magnetic modulator. The magnetic modulator has a magnetic core with a primary winding and a secondary winding around it. The pulse forming network includes an inner winding of flattened wire around the magnetic core and connected to one end of the secondary winding for receiving an induced voltage. The pulse forming network also includes a metal foil shield around the inner winding, so that the induced voltage may be stored capacitively between the inner winding and the shield. When the magnetic core saturates, the impedance of the secondary winding drops, so that the pulse forming network discharges through a load. The shape of the pulse through the load is determined by the inductance of the inner winding and the capacitance between the inner winding and the shield.

Abstract: Utilizing sections of charged transmission line cables and optically-actied semiconductor switches, the direct generation of high power RF is demonstrated.

Abstract: A device for radiating pulses of radio frequency energy in response to pulses of laser light in which a metal layer is ohmically bonded to one side of a substrate of semiconductor material and an antenna is ohmically bonded to the other side of the substrate, there being at least one aperture in the metal layer for permitting laser light to reach the disk.