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: An electromagnetic launcher or railgun includes a projectile or armature which is comprised of an optically activated semiconductor switch device including a body of bulk semiconductor material, such as gallium arsenide (GaAs) or gallium arsenide doped with chromium (Cr: GaAs), located between a pair of rails across which is connected a relatively high current source. A source of optical energy, such as a pulsed laser, directs optical energy to at least one surface of the semiconductor switch device where the conductivity of the semiconductor body is thereby increased and current from the source is transferred between the rails through the semiconductor body, causing an electromagnetic Lorentz type drive force to be built up behind the armature, which is set into motion and rapidly accelerated along the rails.

Abstract: A Marx high voltage generator with a fast rise time. Photoconductive semiconductor switches are sequentially triggered by a single laser via fiber optic bundles of different lengths. The switches serve to series connect a group of charged capacitors. Output is taken from the last capacitor which receives the voltage accumulated on all of the previous capacitors. Proper timing of the activation of each switch produces a fast rise time.

Abstract: A high power solid state source of microwave and millimeter wave signals is provided by an optically triggered body of bulk semiconductor material selected from the Group III-V compounds including GaAs, Cr:GaAs, and Fe:InP and having a relatively long gap length which is in the order of 0.5 to 10.0 mm as well as having a resistivity which is greater than 1.times.10.sup.7 ohm-cm. The device is further dc biased to a field of between 15 kV/cm and 35 kV/cm. Under such conditions, a very low dc current flows without any oscillatory behavior; however, illumination of the semiconductor body with a fast rising optical pulse having a wavelength suitable for carrier generation causes electrons to be lifted to the conduction band which is accompanied by a rapid reduction of the resistivity.

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: High power optically activated switches of the semiconductor type utilizing broadbanded flashlamp as the source of light for rendering the semiconductor conductive and thus close the switch. In order that the conductivity of the semiconductor when in the "on" state be uniform over the load current carrying cross-section thereof, the semiconductor is treated to produce a tapered density of trapping or re-combination centers therein, with the density being a maximum at the semiconductor surface which faces the flashlamp. Several novel configurations of these switches are shown, including reflectors for concentrating the flashlamp output on the semiconductor, and a plurality of semiconductor switches all activated by a single light source, as well as liquid cooled semiconductors.

Abstract: Narrow pulse modulation (less than four nanoseconds) of millimeter wave ts will enable radar systems to achieve improved pattern recognition. The modulator has an outer cylindrical return shield surrounding a tetrode thyratron. An inner cylindrical shield connected to the anode provides capacitive energy storage for generating the output pulse when the control grid is triggered. The anode is connected via only a resistance to the direct current supply.

Abstract: A pulse generation system using an inductive energy storage technique is described. A high magnitude current flowing in a storage inductor is suddenly halted by means of a repetitive series interrupter device and an accompanying magnetic field coupled control circuit. The resulting high voltage generated causes breakdown across a spark gap and transmission of a high energy pulse to a load.

Abstract: A vector inversion stacked stripline pulse generator adapted for single sch initiation consisting of a relatively long laminated assembly of alternate layers of dielectric and metallization wound on a non-magnetic cylindrical form with the metallization layers interconnected as two separate sets of mutually overlying conductors which are selectively connected together in a spiral around the outer periphery of the cylindrical form, thereby providing a compact pulser which is capable of providing a relatively faster risetime output pulse over conventional designs.

Abstract: A high energy, optically controlled kilovolt semiconductor switch is provd including a bulk piece of high resistivity semiconductor for illumination by a high speed laser, said semiconductor having a thick highly doped epitaxial layer of P+ impurity grown on one side of the semiconductor, and a thick highly doped epitaxial layer of N+ impurity grown on the opposite side of the semiconductor with metallic electrodes deposited on the respective epitaxial layers using standard ohmic contact procedures.

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