Abstract: A microwave/millimeter wave circuit structure supports discrete circuit elements by flip-chip mounting to an interconnection network on a low cost non-ceramic and non-semiconductor dielectric substrate, preferably Duroid. The necessary precise alignment of the circuit elements with contact pads on the substrate network required for the high operating frequencies is facilitated by oxidizing the interconnection network, but providing the contact pads from a non-oxidizable material to establish a preferential solder bump wetting for the pads. Alternately, the contact bumps on the flip-chips can be precisely positioned through corresponding openings in a passivation layer over the interconnection network. For thin circuit substrates that are too soft for successful flip-chip mounting, stiffening substrates are laminated to the circuit substrates.

Abstract: A passive intermodulation shield (10) for a spacecraft is made from a substrate (12) and a vacuum deposited aluminum layer (14) over the substrate (12). The substrate (12) can include a polyimide sheet such as Kapton. The vacuum deposited aluminum layer (14) has a thickness (16) to produce a surface resistivity which maintains both the inherent passive intermodulation generation and the passive intermodulation passthrough below a predetermined value. Preferably, the surface resistivity is selected between 10 ohms per square and 40 ohms per square. Spacecraft multilayer insulation blankets (30, 40, 50, 60) are formed by disposing the passive intermodulation shield (10) between a pair of outer layers.

Abstract: A satellite-based communication system providing high rate transfer of data between linked terminals. The system comprises a plurality of user terminals (VSAT's) that are linked by and that communicate with each other by way of a satellite-based relay system. A network control center provides configuration signals that control the satellite relay system and coordinate linking of terminals to each other. Frequency division multiplexing uplinks are used from the terminals and the network control center to the satellite relay system. Time division multiplexing are used on downlinks from the satellite relay system to the terminals and the network control center. Each user terminal comprises a data compression and decompression circuit, a transceiver, and an antenna for transmitting and receiving data to and from the satellite relay system. The satellite relay system comprises a satellite, a wide area antenna, a plurality of receive antennas, a plurality of transmit antennas, and a signal processor.

Abstract: An apochromatic grism (42) includes a first prism (48) with a second prism (50) disposed adjacent to it. A grating (44) is adjacent to the front surface of the first prism (48) and the Abbe number and dispersion coefficient of the grating are chosen such that the primary and secondary angular spread for a given spectral band is approximately zero. The apochromatic grism is a simple and compact device with minimal amounts of residual chromatic and anamorphic aberrations.

Abstract: A membrane probe (10) for simultaneously testing two or more columns or rows of integrated circuits (37) while still on the wafer (56) upon which they are manufactured includes a flexible visually clear and self planarizing membrane (18) having circuit traces (22). A substrate (12) on which the membrane (18) is mounted features parallel ports (14) corresponding to alternate columns or rows of circuit chips (37) on the wafer to be tested. Two such substrates (12,112) thus forming two alternately used probe test heads (10,110) are employed for testing each full wafer, one test head (10) containing ports (14) corresponding to one set of alternate wafer columns or rows, the other test head (110) containing ports (114) corresponding to the remaining interlaced wafer columns or rows. Probe contact pads (30) are electroplated on areas of the traces (22) so that the contact pads (30) are visually registrable through the substrate ports.

Abstract: A wide-bandwidth variable attenuator/modulator incorporating a region of material comprising a combination of a ferromagnetic/nonmagnetic material which exhibits a Giant Magnetoresistance (GMR) effect.

Abstract: A digital receiver apparatus and method, designed for multiple simultaneous users, digitizes a received analog RF signal and tunes to multiple desired frequencies of the received signal on a time division multiplexed basis. After filtering by a finite impulse response (FIR) filter that also operates in time division multiplexing for multiple service bands, the selected signals are digitally demodulated and signal processed, again on a time-shared basis. Different service bands are accommodated at the same time by separate FIR filters, each including a coefficient memory for its particular service band. The multiplexed frequency signal for each band is multiplied by the coefficients of its respective FIR filter memory in a common complex multiplier. The results are demultiplexed and directed to respective accumulators for decimation in accordance with the FIR coefficient characteristics.

Abstract: A projection cathode ray tube having an improved target assembly (22) for minimizing target tilt and hot focus drift is disclosed. The target member (24) is supported by a shaft screw (37) secured to a face plate (20) of the projection tube by an adjustment pad (58) external to the tube in cooperation with a biasing spring (46) internal to the tube that exerts a tensile load on the shaft screw (37). A shaft screw tapered shoulder (36) and threaded mounting stud (34) engage a tapered seat (32) and threaded mounting bore (30) of the target (24), with the taper angle (.theta.) common to the shoulder and seat calculated to maintain constant contact between the abutting surfaces of the shoulder (36) and the seat (32) during thermal expansion and contraction of the target member (24) and shaft screw (37).

Abstract: A high power, flip-chip microwave monolithic integrated circuit (MMIC) assembly (30) has a high power microwave monolithic integrated circuit (MMIC) having a surface with an active area (72) in which heat is generated. The assembly also has a host substrate (34). A thermally conductive bump (51) formed over the surface of the MMIC has a first portion (51') in close proximity to and in thermal communication with the active area (72) of the MMIC and a second portion (51") which is in close proximity to and in thermal communication with the host substrate (34). The second portion (51") of the thermal bump (51) has a greater cross-sectional area than the first portion (51'). A multi-layer, multi-exposure method of manufacturing the improved thermal bump (51) includes several steps. A plating membrane (80) is formed on a surface of the MMIC (32). A first layer of negative photoresist is applied to the surface of the plating membrane (80), and is exposed with a first masked pattern of light.

Abstract: An adaptive processor which uses the successive range and Doppler outputs of a conventional matched-filter to improve the signal-to-noise ratio for non white noise/clutter. The adaptive processor minimizes the output for a given range and Doppler cell with the constraint that the response to signals returning with specified range and Doppler offsets, with respect to the center of the range-Doppler cell, each have specified values. Weights are derived which can be applied to range-Doppler outputs in the neighborhood of the range-Doppler cell to minimize its output subject to the constraints. The weights depend on an estimate of the cross-covariance matrix of the various outputs of the range-Doppler cells that are to be weighted. The constraint parameters are specified in terms of the ambiguity function of the transmitted waveform.

Abstract: An integrated solar cell-bypass diode assembly is provided by forming at least one recess in the back (non-illuminated) side of the solar cell and placing at least one discrete low-profile bypass diode in respective recesses so that each bypass diode is approximately flush with the back side of the solar cell. Each bypass diode is bonded to the solar cell for anti-parallel connection across the solar cell. The back side of the solar cell is preferably formed with a honeycomb pattern of recesses to reduce the weight of the solar cell while maintaining mechanical strength. The recesses that receive bypass diodes preferably have a rectangular shape that better accommodates the bypass diode.

Abstract: A bandpass microwave filter (32) is constructed by use of a right cylindrical cavity resonator (10) wherein end regions (22, 24) of the resonator are tapered. The tapering is accomplished by replacing end portions of a right cylindrical sidewall with frusto-conic sections (22, 24) of side wall. Each frusto-conic section joins a central cylindrical section (26) of the sidewall with a planar end wall (14, 16). Each of the end walls is provided with a coupling slot (28, 30) having dimensions substantially smaller than a half wavelength of the center resonant frequency of the resonator so as to be a nonresonant slot. The slots in the end walls may be coupled to rectangular waveguides (34, 36) which form input and output ports by which electromagnetic signals are applied to and extracted from the resonator.

Abstract: A diamond matrix metallic mesh suppresses RF energy, and particularly side lobe energy, in a phased array antenna, while passing main beam energy. The metal mesh emulates the structure of the bond segments joining the carbon atoms in a diamond structure. The wire diamond lattice structure is placed above an array of radiating elements to absorb side lobe energy. The wire lattice structure is fabricated through use of complementary forms which compress a wire into a required unit shape. Many unit shaped wires are placed in a form which hold the wires in the proper position. Other unit shaped wires are rotated 90 degrees and attached in place to the held wires. Additional unit shaped wires are added to form the basic interlocking cube structure of the diamond lattice.

Abstract: A system and technique for measuring the thickness of an optical element. A first energy signal of a first phase is transmitted into the element. The first signal reflects off of a distal surface of the element and is detected as a return signal. The phase of the reflected signal is compared to the phase of the transmitted signal and the frequency varied to extract a third signal representing a desired phase difference therebetween. Corresponding frequency data are processed to determine the thickness of the element at the point of transmission of the first signal.

Abstract: Discrete carrier and lattice structures are bonded together to form a lightweight rigid solar panel. The carrier includes a pair of electrically inert face sheets bonded on opposite sides of a thin thermoconductive honeycomb core. The face sheets provide an electrically inert surface for receiving a solar cell array and the honeycomb core forms a heat sink for conducting heat away from the solar cell array. The lattice includes a pair of patterned face sheets having a high elastic modulus bonded on opposite sides of a lattice base. The patterned face sheets provide axial stiffness and the lattice base separates them to provide bending stiffness. By splitting the solar panel into discrete carrier and lattice components, the present invention reduces the weight of existing solar panels by approximately 40% and increases power efficiency by approximately 10%.

Abstract: A liquid crystal light valve is provided with an array of photoconductive pedestals surrounded by a dielectric matrix material. Metal mirror pads are formed on top of each pedestal to form a high resolution metal matrix mirror, with each pedestal/mirror combination servicing one image pixel. The dielectric matrix forms a potential barrier between the individual photoconductive pedestals which prevents lateral charge migration between pedestals. The metal matrix mirror also shields the underlying photoconductive pedestal from photoactivation by the readout beam. The dielectric matrix material has a lower dielectric constant than the photoconductive pedestals, allowing the impedance of the photoconductive pedestals to match the impedance of the liquid crystal layer with a much thinner layer of photoconductive material than in prior LCLVs using a continuous photoconductive layer.

Abstract: Input RF signals to a transponder, such as a communications satellite, are down converted to a lower intermediate frequency (IF) that is common for each different channel. The channel signals are all processed at the common IF, and then up converted to different respective transmission frequencies. This allows for a down conversion/signal processing/up conversion unit design that is the same for each channel (except for frequency and gain values), and facilitates the use of inexpensive available standard components as well as low bandwidth channel filters. An improved phase noise cancellation phase lock loop (PLL) is preferably used to generate tuning signals used in the up and down conversion processes. The PLL includes two loop mixers, with the down and up conversion mixing signals taken respectively from the inputs to the first and second loop mixers. The first and second loop mixers receive mixing signals at frequencies (T-R) and (T-IF-N.multidot.

Abstract: A modular jet spray device for use in cleaning submicron sized particles and molecular films using CO.sub.2 spray. The modular jet spray device comprises a valve body having first and second ends and an gas input for receiving a CO.sub.2 cleaning agent. A jet spray nozzle is removably secured to the first end of the valve body and comprises an input orifice and an output orifice. A sleeve assembly is removably secured to the second end of the valve body, and a needle assembly is removably secured to the sleeve assembly. The needle assembly has a needle that inserts into the input orifice of the nozzle. A micrometer is removably secured-to the sleeve assembly distal from the valve body and is coupled to the needle assembly for adjusting the position of the needle relative to the inlet orifice of the jet spray nozzle. A CO.sub.2 gas source is coupled to the gas input of the valve body. Optionally, a filter may be coupled between the CO.sub.2 gas source and the gas input of the valve body.

Abstract: An epitaxial structure and method of manufacture for a single heterojunction bipolar transistor capable of being utilized in high-speed and high-power applications. Preferably, the epitaxial structure comprises an N-type collector made from InP, a P-type base made from InP, and an N-type emitter made from a semiconductor material of approximately 39 mole percent AlP and approximately 61 mole percent Sb.

Abstract: A method for filtering actuator commands for a satellite control system to reduce resonant mode excitation despite uncertain knowledge of the resonance frequencies, due to parameter variations, nonlinearities, and the like. The present method filters the actuator commands with staggered proportional plus delay (posicast) filters having distinct delay values, chosen to provide a desired resonance attenuation over a resonance uncertainty range. The present method may be extended to filter multiple resonances by cascading the staggered filters for each resonance. The present invention has wide application, such as in spacecraft precession and translation maneuvers, as well as gimbaled payload stepping. A particular advantage of the present invention is its direct applicability to fixed-amplitude actuators (such as thrusters and stepper motors), and reduced excitation of resonances at frequencies above those of primary concern.