Abstract: Reduction in the base to collector capacitance of a heterojunction bipolar transistor, and, improved high frequency performance is achieved using existing materials and processes by undercutting the collector (5) under the base (7) along two parallel sides of the base mesa (7—FIG. 4), and providing a sloped collector edge (5—FIG. 6) along the remaining two parallel sides of the base. The foregoing is accomplished by selective etching and with the four sides of the mesa regions oriented as a non-rectangular parallelogram (7, 9—FIG. 4) in which one pair of sides is in parallel with one of the said [0 0 1] and [0 0 {overscore (1)}] planes of the crystalline structure and the other pair of sides in parallel with one of the [0 1 1] and [0 {overscore (1)} {overscore (1)}] planes of the crystalline structure.

Abstract: An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a folded optics antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed is coupled to a feed network which acts to combine the illumination beams of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate predetermined location on the subreflector which directs the illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth.

Abstract: A method for fabricating an integrated circuit which reduces steps in the integrated circuit comprising the steps of depositing a first conductive material layer over the first dielectric material layer and patterning the first conductive material layer to form a first conductive pattern. A second dielectric layer is then deposited over the first conductive pattern and the exposed portions of the first dielectric material layer. A planarizing material layer is applied over the second dielectric material layer and cured such that the planarizing material layer produces a substantially planar top surface. The planarizing material layer and portions of the second dielectric material layer are removed in a manner which maintains the substantially planar top surface until only a preselected amount of material remains over the first conductive pattern.

Abstract: A method for transferring a data packet, in a connectionless manner between a first source terminal and a first destination terminal, in a communications network which supports connection-oriented communications. The data packet is segmented into one or more cells with a portion of each cell comprising the cell header. A preselected value is place into the cell type identifier field to indicate that the cell is to be sent in a connectionless mode. A source terminal identifier is assigned to each source terminal in the network and the source terminal identifier corresponding to the first source terminal is placed into each cell header. A preselected value is placed into the information field to be used by the network to route the cells from the first source terminal to the first destination terminal. The cells are routed though the network and broadcasted over the downlink antenna beam which covers the first destination terminal.

Abstract: A multi-pattern antenna for providing a plurality of antenna patterns at different frequencies or polarizations from a single reflector body eliminates the need for multiple reflector antennas on a single spacecraft. The reflector antenna comprises a reflector body and an illumination source. The illumination source illuminates the reflector with a plurality of RF signals each of a preselected frequency or polarization. The reflector comprises a plurality of zones with each zone reflecting preselected RF signals. A plurality of antenna patterns are generated from the reflected RF signals. Each zone is sized to a preselected shape such that the antenna patterns have a desired shape or beamwidth characteristic.

Abstract: A fully optical converter for converting an analog signal into a digital signal includes an amplitude to optical wavelength converter for converting the analog signal into an optical signal which varies in wavelength in accordance with an amplitude of the analog signal, a splitter for applying the optical signal over a desired number of light paths, an interferometer connected to each of the light paths, unequal path lengths in each leg of the interferometers to allow optical interference to deliver a complementary sinusoidal transfer function to the optical signal to generate two complimentary output signals and a dual detector connected to each of the interferometers for generating a digital bit in response to the two complimentary output signals, wherein each of the digital bits together form a parallel digital word. The fully optically based converter is automatic and independent of interactive techniques, thus providing for an expedited conversion rate.

Abstract: A reflection reducing directional coupler provides an output signal from a coupled signal while reducing the effect of an input signal. The directional coupler provides circuitry to divide, phase delay and vectorially add signals to provide coherent output and coupled signals and reduce reflected signals. The directional coupler also provides the capability to input a calibration signal into a system while mininimizing the effect of the calibration signal on the output signal.