Abstract: A tubular blank from which a slow-wave structure is to be formed is mounted on a mandrel in front of and spaced slightly from an electrode having a predetermined pattern of slots corresponding to areas along the tubular blank from which material is not to be removed. The blank and the electrode are connected to an electrical discharge machine to establish electrical discharges between the blank and the electrode, and the mandrel and the blank carried thereby are simultaneously advanced and rotated past the electrode. Portions of the blank adjacent to the non-slotted surface portions of the electrode are removed, while the portions of the blank adjacent to the slots in the electrode are retained.

Abstract: A feed-forward microwave amplifier arrangement is disclosed havaing an error-detecting loop including a main amplifier branch and a phase-shift branch, as well as an error-canceling loop including an auxiliary amplifier branch and a phase-shift branch. A temperature compensating arrangement including a ferrite slab centrally mounted in a stepped rectangular waveguide is provided in the phase-shift branch of the error-canceling loop. The temperature compensating arrangement has a phase versus temperature characteristic similar to that of the auxiliary amplifier. An additional ferrite temperature compensating arrangement, having a phase versus temperature characteristic similar to that of the main amplifier, may be provided in the phase-shift branch of the error-detecting loop.

Abstract: The disclosed microwave distributed amplifier includes a plurality of cascaded field emission triodes, each having a field emission element for emitting electrons, a grid disposed downstream from the field emission element along the electron flow path and an anode disposed further downstream along the electron flow path. A series of inductive strips interconnect successive grids to form a grid transmission line, while another series of inductive strips interconnect successive anodes to form an anode transmission line. Small electron transit times over integrated circuit distances in a vacuum environment and low interelectrode capacitance allow extremely large gain-bandwidth products to be achieved.

Abstract: A double barrier tunnel diode, wherein a central quantum well is disposed between a pair of barrier layers to form a quantum barrier, the barrier layers having a composition such that a resonance energy level is created in the quantum well layer, and having a thickness sufficiently small that electrons can tunnel through the quantum barrier under an applied voltage. The quantum well and barrier layers are disposed between two electron injection layers having compositions selected so that the conduction band minimum energy for electrons in the injection layers is about that of, but less than, the resonance energy level of the quantum well. Electrons pass through the quantum barrier by tunneling, upon application of a small voltage across the double barrier tunnel diode sufficient to raise electrons near the conduction band minimum energy of the injection layer to the resonance energy level of the quantum well.

Abstract: The device provided is a GaInAsP/InP laser, of the buried heterostructure type, fabricated by a two-step liquid-phase epitaxy technique. The active region is defined by a mesa etch to achieve low threshold current and a single transverse optical mode. The mesa is subsequently buried by a second step of liquid-phase epitaxy for optical and current confinement. A low bandgap heterobarrier is employed to reduce leakage current near the active region at high current biases. A contact layer is grown directly over a majority carrier confining clad layer to reduce defects in the crystal face on the side of the clad layer, and thereby further reduce leakage current.

Abstract: A light detector (10) comprising a detector cell (12); a system for focusing light (14, 16, 18) on the cell; a liquid crystal (22) positioned in the light path; the liquid crystal (22) being prepared so that it passes light along the light path in the normal operating range of the detector cell (12) and directs light away from the light path when a threshold intensity of light is reached; and source of bias (24) across the crystal to enhance the recovery of the crystal (22).

Abstract: A resonant quantum well laser incorporates semiconductor barriers on one or both sides of the quantum well to increase the charge density within the quantum well. The composition of the injection layers can be tailored in a manner that the energies of the charge carriers in the injection layers are about that of a resonant energy level for that type of charge carrier in the quantum well. The barrier layers on one or both sides of the quantum well enhance the probability of the charge carrier being in the well for a longer time and travelling a longer distance, increasing the chance of scattering. The charge carriers, electrons or holes, can move from their respective injection layers into nearly identical energy levels within the quantum well, by tunneling through the thin barrier layers. The number of carriers which are available to transfer into the lasting energy level is increased, thereby increasing the efficiency of the laser and lowering its threshold current.

Abstract: A solid-state system and method for extracting heat from a given load which includes connecting a first diode heat pipe between an electrocaloric heating and cooling element and a load and a second diode heat pipe between the electrocaloric heating and cooling element and a heat sink. By appropriately pulsing the electrocaloric element to provide continuous heating and cooling thereof, heat may be continuously extracted from the load and through the two diode heat pipes to a heat sink.

Abstract: A three-dimensional integrated circuit structure utilizing a hybridization of silicon-on-insulator and silicon-on-sapphire technologies is disclosed, wherein a buried doped epitaxial silicon layer, insulated from a gated semiconductor device by a buried insulating layer, biases the gate region of the overlying semiconductor device, thereby providing a second gate positionally opposed to the conventional first gate of the semiconductor device. The second gate (or backgate) is utilized to draw undesired charge carriers from its overlying insulating layer, thereby avoiding the undesirable effects of the presence of such excess charge carriers, which typically may be induced by external radiation. The selectable backgating feature is fully compatible with existing integrated circuit fabrication technology, and may be utilized to provide a single backgate for all overlying semiconductor devices, or individual backgates for one or groups of semiconductor devices in island-etched structures.

Abstract: A radar transceiver is disclosed which operates with circularly polarized waveforms. A single circularly polarized antenna is used to transmit and receive circularly polarized waveforms. A 3-dB directional coupler splits the signal to be transmitted into two signals 90.degree. out-of-phase for transmission by the antenna and also combines the horizontal and vertical components of any return signal.

Abstract: Helical slow-wave structure (10) carrying three ceramic support rods (12, 14, 16) is inserted with clearance into the bore (22) of malleable barrel (20). Dies (24, 26) close around the barrel to malleably coin the barrel and close it down around the support rods to engage the support rods by interference fit to accurately support the helix (10) and provide thermal conductivity therefrom.

Abstract: A plurality of longitudinally disposed dielectric support rods are attached to the outer circumferential surface of a helical slow-wave structure to form a subassembly. The subassembly is mounted in a light press-fit relationship within an enveloping structure comprising a plurality of annular nonmagnetic spacer elements repectively interposed between and abutting a plurality of annular ferromagnetic pole pieces. Plastically deforming force is applied by means of a pair of dies to the outer surface of the spacer elements to crimp the spacer elements onto the support rods and thereby firmly hold the slow-wave structure-rod subassembly within the enveloping structure.

Abstract: A method for providing deep impurity doped regions under the back contacts of a solar cell. In a semiconductor wafer with a p-n junction therein defining an n+ layer emitter and p-type layer bulk, a p+ layer is formed in the p-type layer under the back surface of the wafer. An oxide passivation layer is disposed over the back surface. Metal paste is screen printed onto the oxide layer in a predetermined pattern. The combination is heated to a temperature such that the metal paste will drive through the oxide layer and alloy with selected regions of p+ layer and p-type layer to a predetermined depth forming heavily doped p+ impurity regions. Metallization is applied onto the oxide layer making electrical contact with the heavily doped p+ impurity regions.

Abstract: A gallium arsenide solar cell is disclosed which employs a front aluminum gallium arsenide window layer. Metallic grid lines for charge carrier collection traverse the window layer and extend through this layer to the emitter layer. A flat conductive bar on the window layer crosses and makes electrical contact with the metallic grid lines. A flat metallic strip located on the window layer near an edge is spaced from the grid lines and conductive bar but is electrically coupled to the conductive bar by metallic bridges. Since the metallic strip is not in contact with the grid lines, external electrical connections can be affixed to the flat metallic strip using high temperature welding or soldering techniques without damage to the semiconductor body.

Abstract: A gallium arsenide solar cell is disclosed having an aluminum gallium arsenide window layer in which fine metallic contact lines extend through the aluminum gallium arsenide window to electrically contact the emitter layer, and a plurality of metallic grid lines disposed on the window layer cross the contact lines, thereby making electrical contact to the metallic contact lines. A flat metallic strip extending along one of the edges of the solar cell electrically couples the grid lines to one another. Consequently, two separate metals can be used, one with good ohmic contact properties for the grid lines and another with good adhesion and current conducting properties for the current collecting bars. Additionally, the metallic contacts lines can be made very narrow to reduce the contact area to the emitter thereby reducing the recombination current in the emitter.

Abstract: Ion pump (10) has feedthrough (33) for electrical connection to anode post (32) within the pumping chamber. Opening (36) in the pumping chamber wall receives a portion of insulator (42). The insulator (42) has a flange (48) which is of larger diameter than the opening (36) so that sputtered cathode material cannot directly disposit on the outer and upper surfaces of the flange (48).

Abstract: An electrical interconnection assembly is disclosed for use with high voltage devices such as traveling-wave tubes. The assembly includes an electrically insulating housing having a plurality of recesses formed in its outer and inner surfaces. Leads from the high voltage device can be connected directly to respective conductive pins mounted in recesses in the housing inner surface, and electrical conductors from a power supply can be connected directly to respective conductive pins mounted in recesses in the outer surface of the housing and which are electrically connected to respective conductive pins on the inner surface. Protruding staggered gripping elements on the housing outer surface and on a removable cover plate for the housing minimize the possibility of separation of electrical conductors from the conductive pins.

Abstract: An improved pole piece structure for periodic-permanent-magnet focused traveling wave tubes is disclosed. In one embodiment, the pole pieces have two fold symmetry and the magnets are arranged about the tube axis in a pattern with two-fold symmetry. This structure accommodates the input or output waveguides while maintaining the symmetry of the magnet placement. This allows the electron beam to remain centered on the tube axis and, therefore, minimizes beam interception. Circuit heating is reduced and the power handling margin of the tube is increased in comparison to conventional TWT structures. In another embodiment, a triangular pole piece configuration is employed, eliminating displacement of the magnets at the coupler and sever cavities and providing a third cooling channel.

Abstract: A process is disclosed for preparing selectively doped and recrystallized silicon-on-insulator semiconductor wafers, and wafers prepared thereby, wherein successive amorphizing and annealing sequences are utilized to optimize the defect structure and doping of multiple regions or islands of the silicon on an insulator substrate. Prior to fabrication of the active devices, the various silicon islands are given customized ion implantation treatments to amorphize a silicon near-interface layer under differing sets of implantation conditions. The entire wafer is then annealed to achieve downward epitaxial recrystallization of the amorphized near-interface layers in all of the amorphized islands, growing on the near-surface crystalline layer of the silicon remote from the interface. The near-surface layers of the islands are then amorphized and annealed to achieve upward epitaxial recrystallization of the layers on the underlying silicon layer.

Abstract: Seal (40) between travelling-wave tube electrodes (32 and 34) includes an inner hermetic seal ring (50) for providing vacuum sealing and an outer ring (52) which shares the mechanical stresses due to changes in temperature.