Abstract: An integrated, interdigitated capacitor incorporates all layers of an I.C. fabrication process into its design to produce a multi-layer high-capacitance device. For example, a "two-metal, two-poly" CMOS fabrication process is used to produce a capacitor having five interdigitated conductive plates, which when interconnected produce a total capacitance at least twice as great as a conventional two-plate capacitor of the same area, while requiring no additional I.C. processing steps. The invention's conductive plates and interconnections are arranged so that interconnection traces stay within strict design limits intended to insure reliable connections, while keeping the area required for the interconnections small.

Abstract: An electromagnetic wave component uses one or more diaphragms secured to the interior of a waveguide structure to tune its resonant frequency, with each diaphragm engaged by one or more adjustment members that deform it. The adjustment members are preferably screws that are threaded through the structure to push and/or pull on the diaphragms, thereby tuning the electromagnetic wave component. The shift in the resonant frequency of the electromagnetic wave component due to temperature-induced dimensional changes is mitigated if the materials used for the diaphragm, the adjustment members and the structure which houses the diaphragm are chosen to have an appropriate combination of thermal coefficients of expansion.

Abstract: An electronic component operating at high voltage is mounted to the top side of an insulating platform, which in turn is supported from a chassis by a pedestal. The insulating platform provides a long surface path conduction distance of the electronic component to the chassis and to other components mounted to the chassis. The platform-mounted electronic component is thereby insulated against arcing and damaging the other components.

Abstract: A modular payload support for placement in an enclosure defined by the sidewalls of a launch vehicle includes a central hub, a plurality of trusses, and a plurality of modular outer panels. Each of the trusses includes an inner edge secured to the hub and extends radially outward from the hub. Each of the trusses further includes an outer edge, and a modular outer panel is secured to each of the truss outer edges. Each modular outer panel is adapted for attachment to the vehicle sidewall, with each modular outer panel being sized to span the available distance between the truss outer edge and the vehicle sidewall. Each of the trusses is constructed of a number of layers or plies, so that the trusses may be tailored to meet strength and stiffness requirements of a contemplated application.

Abstract: An improved dual gridded reflector antenna configuration which allows cross-polarization radiation to be scanned in any given direction. The dual-gridded reflector assembly includes a front parabolic reflector illuminated by a first source, and a second parabolic reflector illuminated by a second source. The second reflector is positioned adjacent to and behind the front reflector such that the center points of the reflectors align to define a center axis. Additionally, the first and second sources are positioned at different offsets with respect to the reflectors and have a respective rotated offset angle with respect to the center axis such that the sources define an antenna feed separation. By modifying the offsets and the rotated offset angles, the feed separation can be designed to have an inclination with respect to the north-south or east-west feed separation direction.

Abstract: A reflector system for a solar wing is provided in which adjacent reflector panels are inhibited from relative movement by coupling tethers. Each reflector panel rotates to be in a stored position adjacent a backface of a respective solar panel. From this stored position, each reflector panel then rotates to be in a deployed position in which it forms a reflection angle with a solar cell face of the respective solar panel. Because of the inhibition of the tethers, the reflector panels deploy together so that one of them does not move past another of them and damage its reflection surface. Upon deployment of a solar wing, a set of spring-biased reflector sheets are automatically urged to cover respective apertures which facilitate installation of restraint structures that maintain the solar wing in its stored configuration.

Abstract: A friction retaining device for holding and releasing reflector panels of a satellite. The retaining devices having a friction bushing mounted thereon to prevent the reflectors from becoming disengaged from the clamp. The retaining device has a pair of opposing arms having upper ends that communicate with bumpers on the reflectors and lower portions that communicate with a release mechanism. Upon actuation of a pyrotechnic device, the reflectors are deployed. At the same time, the release mechanism disengages the lower portions of the opposing arms allowing them to remove the bumpers from the reflectors.

Abstract: A low cost highly integrated method of fabricating a heat sink on the backside of a power semiconductor device maintains device performance, improves thermal transfer, and enables reliable planar connections without having to dice the wafer or package the discrete device-heat sink assembly. An etch stop layer is formed between the wafer and the frontside power devices to protect them during backside processing and to reduce the contact resistance between the device and its heat sink. The heat sinks are formed by thinning, patterning and then plating the wafer in such a manner that the devices can be released without dicing. The heat sinks are preferably oversized so that a vacuum tool can grasp the heat sink from above without damaging the device and then compression bond the heat sink onto a planar microstrip circuit assembly, which is designed and packaged to facilitate easy replacement of failed devices.

Abstract: A motor current sensing circuit using a single sensing resistor in the motor current path to sense the current from the voltage source. The circuit includes an amplifier and a unity-gain inverter that translate the current across the sensing resistor into a voltage analog of the current in the motor. At any instant in time, the magnitude of the voltage across the sensing resistor is proportional to the magnitude of the motor current. During the forward portion of the duty cycle, a high-speed switch connects the sensor output to the amplified sensed bus current analog. During the reverse portion, the sensor output is connected to the inverted bus current analog. The average value of the sensor output is the voltage analog of the average value of the motor current.

Abstract: Methods for the design and fabrication of micro-electro-mechanical switches are disclosed. Two different switch designs with three different switch fabrication techniques are presented for a total of six switch structures. Each switch has a multiple-layer armature with a suspended biasing electrode and a conducting transmission line affixed to the structural layer of the armature. A conducting dimple is connected to the conducting line to provide a reliable region of contact for the switch. The switch is fabricated using silicon nitride as the armature structural layer and silicon dioxide as the sacrificial layer supporting the armature during fabrication. Hydrofluoric acid is used to remove the silicon dioxide layer with post-processing in a critical point dryer to increase yield.

Abstract: A simple joining process for members of passive microwave structures is described which reduces passive intermodulation. The process forms an aperture in a first member and forms a second member to have dimension which exceeds the aperture dimension by a dimension differential. The members are joined by initially causing them to have a temperature differential that is sufficient to permit the second member to be positioned across the aperture. The dimension differential is selected to generate mutually-induced radial stresses in the members, after the temperature differential is removed, which enhance the metal-to-metal contact between the members and, thereby, improve passive intermodulation (PIM) performance. Preferably, the dimension differential is selected to cause the second member to elastically buckle and exert a buckling stress against the first member. Additional interface structures are provided to resist operational axial forces, e.g., vibration, that tend to dislodge the members.

Abstract: A microwave filter has first and second subfilters. Each subfilter has at least one single mode resonator and a preset electrical response. The second subfilter is cascaded to the first subfilter by coupling one of the at least one single mode resonator of the first subfilter to one of the at least one single mode resonator of the second subfilter. The microwave filter has an overall transfer function dependent upon the selection of the first and second subfilters from a plurality of subfilters having different preset electrical responses.

Abstract: A system for simultaneously measuring strains in a test member includes spatial-position members which are coupled to different portions of the test member and first and second displacement sensors which are spaced apart by a sensor space and coupled to the spatial-position members. Linear and bending deformations of the test member are calculated as functions of the responses of the displacement sensors and of the sensor space.

Abstract: A highly uniform, planar and high speed JHEMT-HBT MMIC is fabricated using a single growth process. A multi-layer structure including a composite emitter-channel layer, a base-gate layer and a collector layer is grown on a substrate. The composite emitter-channel layer includes a sub-emitter/channel layer that reduces the access resistance to the HBT's emitter and the JHEMT's channel, thereby improving the HBT's high frequency performance and increasing the JHEMT's current gain. The multi-layer structure is then patterned and metallized to form an HBT collector contact, planar HBT base and JHEMT gate contacts, and planar HBT emitter and JHEMT source and drain contacts.

Abstract: A control circuit for a power supply for at least one Traveling Wave Tube (TWT) that uses the cathode voltage as a reference point allowing independent, variable control of each TWT. The cathode current is varied by varying the anode voltage. Therefore, it is not necessary to operate the TWT below maximum power at full cathode current. The result is improved operating efficiency for the TWT. A single power supply is capable of powering several TWT's resulting in a significant weight and cost savings for space applications.

Abstract: A method of growing a p-type doped Group II-VI semiconductor film includes the steps of forming a lattice comprising a Group II material and a Group VI material wherein a cation-rich condition is established at a surface of the lattice. The method further includes the steps of generating an elemental Group V flux by evaporating an elemental Group V material and providing the elemental Group V flux to a Group VI sublattice of the lattice.

Abstract: A solar power source has a solar power converter, and a solar concentrator positioned to reflect incident light toward the solar power converter. The solar concentrator includes a support having a texture pattern formed thereon, and a reflector surface on the support. The support includes a layer of plastic, and the reflector surface is a layer of a metal, such as aluminum, deposited on the layer of plastic. The texture is formed in the layer of plastic, and is visible on a free surface of the reflector. The texture pattern may be a set of parallel linear recesses.

Abstract: A power system includes at least two battery cell modules. Each battery cell module has a lithium-ion battery cell, and a battery cell controller operably connected to the lithium-ion battery to control the charging and discharging of the lithium-ion battery cell. A central charge/discharge controller is operably connected to each of the battery cell controllers, allowing the charging and discharging of each lithium-ion battery cell to be individually controlled.

Abstract: A method and system for detecting collision of transmitted signals in a random-access, multiple-path communication system utilizes a packet coding arrangement where a transmitting transceiver terminal assembles a plurality of packets into a coded transmit block. Each transmit block is coded with an error detection code, or assigned time slots, so that a routing controller will discard an entire transmit block if any of the packets are not properly decoded. Each transmit block further includes a self-addressed packet, wherein receipt of the self-addressed packet by the transmitting terminal indicates that no collision has occurred. Thus, the present invention does not require any additional circuitry or control of the routing controller, nor transmission of an acknowledgement signal in order to detect collision of transmitted signals.

Abstract: A method and system for providing global variable data rate connectivity in a satellite-based communications network includes a plurality of communications satellites for transmitting and receiving signals in a plurality of coverage areas. User terminals transmit and receive signals to and from the satellites. A set of the user terminals located in one of the coverage areas and associated with one of the communications satellites has a variable bandwidth associated therewith. The variable bandwidth is determined based on the collective bandwidth requirements of each of the user terminals in the set. Each of the user terminals may request a change in their bandwidth requirement independent of the variable bandwidth associated with the collective set of the user terminals.