Abstract: A system (12) operative with at least one electromagnetic wave to produce a circularly polarized wave includes a plurality of polarizer sections (56) disposed along a direction of propagation of one electromagnetic wave. The polarizer sections have opposed rows of phase shifting elements, in the form of rods (76), which are adjusted to provide a match to the orthogonal components of the wave. Penetration and spacing of phase shifting elements within each of the polarizing sections attains a match to the two orthogonal components of the wave and a differential phase shift between the two orthogonal components slightly in excess of a desired 90 degree orthogonal phase relationship. Upon a differential counter rotation between a first and a second of the polarizer sections, the total phase shift introduced by the polarizer sections is reduced to 90 degrees without significant shift in the match of the two orthogonal components.

Abstract: A membrane connector or test probe having a group of connector or test probe contacts (14) in a central contact section of the membrane (12) is initially stretched by being axially displaced from the plane of the peripheral membrane support (10). The test probe is cause to contact the pads (43,44) of device (42) to be tested and is then moved through an over travel distance that tends to decrease the amount of the stretch of the membrane. This decrease in stretch effects a small amount of lateral radial displacement of the test probe contacts to provide a scrubbing action that enhances electrical engagement with a circuit chip pad that may have a poorly conductive oxide coating. Substantially all of the stretch of the membrane is caused to be concentrated in and about the central contact section of the membrane at which the test probe contacts are located.

Abstract: A corrosion resistant barrier is provided for isolated circuity. An isolated circuit (10, 12) with raised interconnection features (16, 18) having a corrosion resistant gold coating (34) is formed on a reusable stainless steel mandrel (22) which is provided with indentations to define raised features. A seed layer (32) of copper is electroplated on the mandrel in a pattern of the isolated circuit to be formed. The copper seed layer (32) is then followed by electroplated layers of gold (34), nickel (36) and copper (38) until a total desired conductor thickness is achieved. A dielectric substrate (44, 46) is laminated on the multilayer conductive traces of the circuit. After removal of the multilayer circuit from the mandrel, a predrilled dielectric coverlay (50) is laminated to the circuit with holes in the coverlay receiving the raised circuit features (52). The finished part is then etched to remove the copper seed layer from the raised features.

Abstract: An arrangement is provided for mounting double ended hermaphroditic signal mode modules (10) that includes an elongated carrier (68) having longitudinal walls (70, 77) and transverse walls (71, 74) that define pockets to receive the connectors (10) and position them accurately so that one set of contact arrays (59) engages contact arrays (86) of a printed circuit board (69) attached to one side of the carrier by a clamping bar (82). Grounding means (87) may be provided at the connections to the printed circuit board (69). The other contact arrays (56) of the connectors (10) face outwardly on the other side of the carrier (68) to engage identical connectors (10). The carriers (68) may be attached to a frame (92) to interconnect printed circuit boards (69) positioned at 90 degrees relative to each other on opposite sides of the frame (92). The carrier (68) may include means (73) to support another connector for supplying power to the printed circuit board (69).

Abstract: An electrochemical storage cell (20) includes a ceramic housing frame (22) with a flat plate solid ceramic electrolyte (32) bonded to a internal shoulder (26) of the housing frame (22) with a glassy seal (33). A metallic weld ring (34) is bonded to each end of the housing frame (22). Each weld ring (34) has a welding flange (36) disposed parallel to a respective end of the housing frame (22) and also has a bonding flange (40). The bonding flange (40) lies parallel and adjacent to an internal surface (24) of the housing frame (22) if the coefficient of thermal expansion of the weld ring (34) is less than that of the housing frame (22), and parallel and adjacent to an external surface (28) of the housing frame (22) if the coefficient of thermal expansion of the weld ring (34) is greater than that of the housing frame (22). A glassy seal (42) is formed between the bonding flange (40) of each weld ring (34) and the respective adjacent surface (24 or 28) of the housing frame (22).

Abstract: A submicron MOSFET is fabricated on an ultrathin layer with a generally intrinsic channel having a dopant concentration less than about 10.sup.16 cm.sup.-3. The channel thickness is preferably no greater than about 0.2 microns; the ratio of channel thickness to length is less than about 1:4, and preferably no greater than about 1:2. Punchthrough and other short-channel effects are inhibited by the application of an appropriate back-gate voltage, which may also be varied to adjust the voltage threshold.

Abstract: A novel, solid-state, low-temperature preparation of barium sulfate provides a higher purity material than that obtained by the conventional method of precipitation. The reaction involves heating a barium oxysalt in the presence of at least one sulfur-containing species for a period of time.

Abstract: A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid level to be measured with a reflector at the first end. The optical fiber extends downwardly through the tank, and its second end is connected to a light source for injecting light into the fiber. The intensity of the input light is compared to the intensity of light reflected from the first fiber end, and the liquid level is calculated from the light loss. The gauge has very high reliability since it has no moving mechanical parts.

Abstract: A liquid crystal is used as the phase modulating medium in a microwave phase modulating cell (20). Applied electric and/or magnetic fields transverse to the direction of wave propagation create a birefringence that changes the velocity of wave propagation and the index of refraction of the medium. The phase modulating cell (20) is used singly or in arrays to direct microwave beams.

Abstract: A microchannel plate array assembly (10), comprising an array of microchannels in a microchannel plate (24), is provided in place of a conventional effusion cell to attain high and uniform fluxes localized in the substrate area for the growth of films thereon by gas source molecular beam epitaxy. Using this approach, an effective pressure at the substrate can be sustained which is as much as 100 times greater than the background pressure in the growth chamber.

Abstract: Data processing systems are described for processing linear programming problems. The invention employs optical (100) or digital (150) processors to perform Gaussian pivot operations by performing outer product matrix operations in parallel. The present invention can solve linear programming problems utilizing various techniques, including the Simplex and Karmarkar algorithms. This results in a greatly improved speed in solving linear programs over prior techniques involving sequential computing.

Abstract: A composite material (20) has electrically conducting, elongated particles (22) dispersed in a liquid crystal (24). The index of refraction to microwaves is controllable by the application of a transverse electric field that aligns the liquid crystal material (24) and the particles (22). A phase modulating cell (31) is formed by placing the composite material (20) inside a microwave wave guide (32), with transverse electrodes (36) built into the sides of the wave guide (32). Another set of transverse electrodes or magnet pole pieces (30) can be provided to align the liquid crystal material (24) and the particles (22) in another direction, thereby switching the index of refraction of the cell (31). The particles (22) may be made of a ferromagnetic material, to permit magentic as well as electrical switching.

Abstract: A grating (22) of narrow parallel ridges (24) is formed in the surface (26) of a substrate (20) made of a hard material such as silicon dioxide. Metal (40) is deposited onto the grating (22) perpendicular to the ridges (24) at an angle of approximately 45.degree. to the surface (26) of the grating such that the metal (40) is deposited onto the top (24a) and one of the sides (24b) of the each of the ridges (24) to form generally L-shaped metal strips (12') thereon. The metal strips (12') are cut at periodic intervals along the ridges (24) to produce anisometric metal needles (12). The substrate (20) is immersed in a dielectric fluid (14), and ultrasonic energy is applied to cause the needles (12) to release from the substrate (20) into suspension in the fluid (14). The L-shape of the needles (12) makes them resistant to bending. The suspension ( 10) has birefringent properties similar to liquid crystals, but may be electrically switched at much higher speed.

Abstract: A miniature, electrostatically actuated, variable impedance circuit element which is operably tunable in response to control signals. With integrated circuit, thin film processing a fixed circuit member is fabricated on a substrate and a movable circuit member is fabricated over the substrate and is movable relative to the fixed circuit member in response to electrostatic fields produced at armature tabs when the control signals are selectively applied to rows of control electrodes. Embodiments include a variable capacitor and a variable ring resonator.

Abstract: A channel layer, donor layer, Schottky layer, and cap layer are formed on a substrate. A source and drain are formed on the cap layer. A gate is formed on the cap layer, or at the bottom of a recess which is formed through the cap layer and partially extends into the Schottky layer. The donor and Schottky layers are formed of a semiconductive material which includes an oxidizable component such as aluminum. A passivation or stop layer of a lattice-matched, non-oxidizable material is formed underlying the source, drain, and gate, and sealingly overlying the donor layer. The stop layer may be formed between the Schottky layer and the donor layer, or constitute a superlattice in combination with the Schottky layer consisting of alternating stop and Schottky sublayers. Alternatively, the stop layer may sealingly overlie the Schottky layer, and further constitute the cap layer.

Abstract: Flaws in an optical fiber are automatically classified as to type by obtaining separate camera images of the fiber illuminated at different angles, and analyzing the images to detect the presence of optical patterns that are characteristic of each different type of flaw. Nominal and actual fiber boundaries are preferably first determined, preferably using noncoherent light, and an initial classification made according to the nature of the differential between the two. An analysis under a side light beam can then be performed to distinguish flaws such as splices, hard versus soft external debris, bubbles, internal debris and uncured buffer. The system reverts to a boundary light analysis to characterize a splice once it has been detected. The boundary analysis is preferably performed with a combination of diffused backlighting transmitted through the fiber, and reflected frontlighting at an angle of about 15.degree.-30.degree. to the fiber axis.

Abstract: Optically sensitive materials (18) such as sensors or the human eye are passively protected against overexposure to high intensity light (20) in the visible region using a reverse saturable absorber (14) comprising one of a class of organic compounds known as buckminsterfullerene, such as C.sub.60. As the intensity of incident light increases, the intensity of transmitted light also increases up to a saturation level, but above the saturation level, the transmitted light intensity remains substantially constant even with increasing intensity of incident light. C.sub.60 has an unexpectedly low threshold for optical limiting action, is thermally stable, and is easily manufacturable into devices.

Abstract: A shaped voltage pulse is applied to a polymer dispersed liquid crystal (PDLC) cell to control its transmission characteristics. The voltage has an initially high level that substantially exceeds the PDLC's threshold voltage. The initial voltage duration is relatively short, and is followed by a gradual reduction of the voltage to a level less than the threshold voltage within a given time frame; the voltage is preferably reduced at a generally exponential rate. Fast response is obtained by setting the initial voltage substantially above the voltage level that corresponds to the desired transmission level in the steady state; the voltage decays from its initial level so that the PDLC transmission actually peaks at the desired range. The shaped waveform forces the PDLC to operate on a hysteresis curve along which the reduction in transmission is delayed as the voltage decays, thereby increasing the cell's optical throughput. The invention is particularly applicable to liquid crystal light valves.

Abstract: A miniature, electrostatically actuated, dynamically tunable circuit which is operable to tune a transmission line in response to control signals. This circuit is micromachined with the use of integrated circuit processes such that a fixed transmission line is fabricated on a substrate and a movable signal line is fabricated over the substrate and is movable relative to the fixed transmission line in response to electrostatic fields produced when the control signals are selectively applied to an array of air bridge stator control electrodes which span the transmission line.

Abstract: A miniature, electrostatically actuated, stub tuner which is operable to dynamically tune a transmission line in response to control signals. With the use of integrated circuit processing the transmission line is fabricated on a substrate and at least one stub tuner is fabricated over the substrate and is movable relative to the transmission line in response to electrostatic fields produced when the control signals are selectively applied to rows of control electrodes.