Abstract: Fatty tissue involved in a liposuction procedure is treated with microwave energy (also known as RF). In a particular embodiment of the invention, the microwave energy is applied by means of a catheter including a suction lumen, an electromagnetic transmission line, and an antenna coupled to the distal end of the transmission line. A microwave generator coupled to the distal end of the transmission line causes radiation from the antenna into the fatty tissue adjacent to the distal suction port of the suction lumen, which tissue is thereby heated and softened. The softened fatty tissue is more readily detached from the adjacent tissue than in the absence of heat, and less mechanical force is required for removal. In another embodiment of the invention, the transmission line is formed so that the electromagnetic field extends into the suction lumen, so that the fatty tissue being removed therethrough continues to be heated.

Abstract: A solar cell voltage regulating arrangement which is particularly advantageous for use in spacecraft includes a light valve such as a liquid crystal cell disposed before the solar cell, to thereby controllably vary the light transmission to the solar cell. A control arrangement varies the transmission of the liquid crystal to control the output voltage.

Abstract: A beamformer for a main antenna and a plurality of auxiliary antennas converts the main and each of the auxiliary signals to digital form. Each of the real and auxiliary digital signals is applied to a pair of real multipliers, in which multiplication by beamforming weights is performed, to produce one weighted real main signal, one weighted imaginary main signal, and a plurality of weighted real and weighted imaginary auxiliary signals. The weighted real main and auxiliary signals are summed together by a cascade of summers, and the weighted imaginary main and auxiliary signals are likewise summed together by another summed cascade. A digital product detector is connected to the output of each summer cascade. The first digital product detector produces in-phase and quadrature components of real detected signals, and the second digital product detector produces in-phase and quadrature components of imaginary detected signals.

Abstract: A rectangular waveguide series junction has a layer of photoconductive material in one branch near the junction. The photoconductive material, when dark, is essentially a dielectric, which effectively increases the dimension of the waveguide branch over what it would be if not modified, thereby increasing its impedance at the series junction and causing power division preferentially into the branch. When illuminated, as by a laser or LED, the photoconductive layer becomes a conductor instead of a dielectric, and the dieletric "increase" in the dimension is eliminated. Instead, the conductive material actually decreases the cross-section, to thereby reduce the actual impedance of the branch at the junction point. This reduces the amount of coupling below that for an unmodified waveguide branch. Thus, the amount of coupling into the branch at the junction is increased by the dielectric constant when the photoconductor is dark, and decreased by the conductivity when illuminated.

Abstract: A power amplifier arrangement includes a power divider for dividing the signal to be amplified into equal-amplitude components. Each component is amplified by a signal amplifying path. The amplified signals are applied to a phase-sensitive power combiner. The combined signal appears at the sum port and a phase-related difference signal appears at a difference port of the combiner. The difference signal is processed to produce a control signal for controlling the relative phases of the signals passing through the signal amplifying paths.

Abstract: For use in a spacecraft for correcting amplifier distortion, a wideband distortion corrector avoids the need for directional couplers. The corrector includes a FET mounted in a miniature microwave-type housing. Signal flows through the source-to-drain channel. A gate impedance selected to be inductive at the operating frequency is coupled from the FET gate to the platform of the package, and may be simply a loop of bond wire. The channel connects by a strip transmission line to an amplifier, the distortion of which is to be corrected. For enhanced bandwidth, an inductor is coupled between the FET source and drain electrodes within the miniature housing. The platform of the package is coupled to the reference conductor of the transmission line. In one embodiment, direct bias voltage is applied by way of a bias tee across a strip transmission line and ground, and galvanic connections cause the bias to appear between the FET gate electrode and the channel.

Abstract: An RF-transparent blanket provides thermal protection against solar and laser radiation. The blanket includes an outer layer of a transparent Kapton dielectric sheet with an outer surface coated with electrically conductive transparent indium-tin oxide to aid in suppressing electrostatic discharge. A second layer includes a transparent Kapton dielectric sheet with a coating of white silicone paint on the surface facing the first sheet. The outermost Kapton sheet protects the paint from long-term damage due to charged particle fluence and ultraviolet radiation. Further sheets of uncoated transparent Kapton, which may be embossed, are interposed between the second layer and a surface upon which an antenna is mounted to provide thermal insulation.

Abstract: A deployable crossed log-periodic dipole array antenna includes a plurality of bays, each associated with four elongated, flexible antenna elements, each element having an S-shaped cross-section for stiffness. Each bay also includes a spool. The spools have a "squared circle" shape adapted to the natural curvature of the antenna elements. A drum surrounds and is coaxial with all the spools, and the antenna elements extend through apertures in the drum. Rotation of the drum winds and unwinds the flexible antenna elements from their spools simultaneously. When the drum begins to wind for retraction of the elements toward a stowed condition, some bays are arranged so that the elements begin to wind about the spools immediately, whereas other bays are arranged so that the antenna elements rotate about hinges over an angle such as 90.degree. or 180.degree. before beginning to wind onto their spools.

Abstract: First and second sandwich panels each have first and second face sheets, held in a mutually parallel, spaced-apart relationship by a low-density core. The panels are joined along an edge, which may be curved. The joinder is made by a plurality of thin, flat "L"-shaped joining pieces, each having first and second legs, which may be at skew angles if the panels are joined at skew angles. The first leg of the first joining piece is affixed, as by adhesive, to the first face sheet of the first panel and to the exposed core of the second panel, and the second leg of the first joining piece is affixed to the second face sheet of the second panel. The second joining piece, adjacent the first, has its first leg affixed to the first face sheet of the second panel and to the exposed core of the first panel, and its second leg affixed to the second face sheet of the first panel. Other additional fasteners may alternate along the length of the edge to be joined.

Abstract: A satellite attitude control system is usable in the absence of any inertial yaw attitude reference, such as a gyroscope, and in the absence of a pitch bias momentum. Both the roll-yaw rigid body dynamics and the roll-yaw orbit kinematics are modelled. Pitch and roll attitude control are conventional. The model receives inputs from a roll sensor, and roll and yaw torques from reaction wheel monitors. The model produces estimated yaw which controls the spacecraft yaw attitude.

Abstract: A spacecraft attitude control system uses one or more momentum or reaction wheels. Wheel bearing viscous (velocity-dependent) friction reduces the actual torque imparted to the spacecraft in response to a torque command signal. Friction compensation is provided by applying the torque command signal to a model of an ideal, friction-free wheel, and calculating the speed which the ideal wheel achieves in response to the torque command. An error signal is generated from the difference between the ideal wheel speed and the actual wheel speed. The error signal is summed with the torque command signal to produce the wheel drive signal. This results in a closed-loop feedback system in which the actual wheel speed tends toward the ideal wheel speed, thereby causing a torque on the spacecraft which is substantially equal to that commanded.

Abstract: A stowable and self-deployable array antenna includes flat, rectangular antenna panels hinged side-by-side so that when deployed they are coplanar, and they fold like an accordion for stowing. The deployed array antenna is stiffened by lateral stiffening panels hingedly attached to every other hinge between antenna panels, and to the unhinged ends of the antenna panels. Foldable longitudinal stiffening panels are hinged between adjacent lateral stiffening panels. Each hinged connection includes a pair of thin spring elements, corresponding to a portion of a cylinder. The two spring elements of each hinge are spaced apart with their concave sides facing, and with the axes of the defining cylinder parallel. The hinge pivots, when the spring elements buckle, about a line orthogonal to a line extending between the cylinder axes. The hinges are used as the structural elements of self-deployable masts. The mast may have a polygonal cross-section.

Abstract: A deployable crossed log-periodic dipole array antenna includes a plurality of bays, each associated with four elongated, flexible antenna elements, each element having an S-shaped cross-section for stiffness. Each bay also includes a spool. The spools have a "squared circle" shape adapted to the natural curvature of the antenna elements. A drum surrounds and is coaxial with all the spools, and the antenna elements extend through apertures in the drum. Rotation of the drum winds and unwinds the flexible antenna elements from their spools simultaneously. When the drum begins to wind for retraction of the elements toward a stowed condition, some bays are arranged so that the elements begin to wind about the spools immediately, whereas other bays are arranged so that the antenna elements rotate about hinges over an angle such as 90.degree. or 180.degree. before beginning to wind onto their spools.

Abstract: A FET is operated without source-to-drain bias, with the source-to-drain conductive path coupled in series with a transmission line. A gate-to-ground impedance is selected in conjunction with a gate voltage near pinchoff to impress nonlinear distortion or gain and/or phase of signals traversing the source-to-drain conductive path. The nonlinear distortion can compensate for the amplitude distortion of a following amplifier, but the phase distortion may not be suitable for correcting that of the following amplifier. An inductor is bridged from source to drain, and corrects the phase without excessive effect on the amplitude. The magnitude of the inductor may be adjusted to minimize nonlinear amplitude change without affecting the phase change, whereupon the phase change may be made independent of amplitude change. A resistor in series with the bridging inductor can be selected to render amplitude change independent of phase change. Two such independent amplitude and phase correctors may be cascaded.

Abstract: A monopulse radar system includes sum and difference receivers, and an auxiliary receive beam offset from the sum and difference beam axis. The received sum and difference signals are processed to produce first and second weighting signals which, when multiplied by the auxiliary signal, produce first and second weighted auxiliary signals which are approximately equal to the magnitude of, and are in a particular phase with, the received sum and difference signals, respectively. In the presence of a jamming signal in the main lobe of the monopulse receiver, the weighted auxiliary signals are summed with the sum and difference signals to produce adapted sum and difference signals, in which the jammer signal is suppressed by a null in the effective receive antenna pattern. The null perturbs the sum and difference patterns, so that the ratios of the sum and difference signals no longer accurately represent the off-axis angle of the target.

Abstract: A multipurpose system provides radar surveillance for air traffic control purposes. The system includes four separate active phased-array antennas, each with .+-.45.degree. coverage in azimuth, from 0.degree. to 60.degree. in elevation. Each antenna element of each phased-array antenna is coupled by a low-loss path to the solid-state amplifier associated with a transmit-receive (TR) module. Each antenna produces a sequenc of pencil beams, which requires less transmitted power from the TR modules than a fan beam, but requires more time beacuse the pencil beam must be sequenced to cover the same volume as the fan beam. In order to scan the volume in a short time, the PRF is responsive to the elevation angle of the beam, so higher elevation angles use a higher PRF. Low elevation angle beams receive long transmitter pulses for high power, and pulse compression is used to restore range resolution, but the long pulse results in a large minimum range within which targets cannot be detected.

Abstract: A communications system includes a transmission channel in which, for efficiency, a processor such as an amplifier is operated in a nonlinear mode. When the signal is modulated in a manner which is affected by the nonlinearity of the processor, such as a multicarrier modulation, a distortion linearizer is used. The distortion linearizer incluees the source-to-drain conductive channel of a FET. The gate of the FET is coupled to ground by an impedance which may be a low inductance, and the gate is biased relative to the channel, possibly near pinchoff, to cause the channel to exhibit desirable gain expansion and phase shifts in response to signal input level, which are selected to compensate the distortion of the nonlinear processor. When the signal is modulated in a manner which is not significantly affected by the nonlinearity of the processor, as for example frequency modulation, the distortion linearizer is switched to a linear or ON mode, in which the amplitude and phase are invariant with signal level.

Abstract: The unknown amount or mass of liquid contained in a storage tank is measured by calibrating the tank in an empty and partially full condition. The calibration includes measuring the mass of the empty tank, and is accomplished by applying a measured amount of heater power or energy to the tank and its contents, and measuring the temperature response to determine the product of total mass multiplied by specific heat. The specific heat depends upon the mass or amount of liquid in the tank, but a linear relationship is established between total mass and the product of total mass times specific heat. The unknown mass of liquid is then determined by applying a known amount of heater power or energy to the tank and its contents, and measuring the temperature rise or rate of rise in response thereto.

Abstract: A radar generates first and second mutually complementary binary code sequences. The autocorrelation functions of the first and second pulse sequences are selected so that, in the sum of their autocorrelation functions, the main lobes add, and the sidelobes are of equal amplitude and opposite polarity, and therefore cancel. The radar sequentially transmits dispersed pulses in which the chips are phase modulated with the two codes. The received pulses are applied uncompressed to the input of a Doppler filter bank, which filters them into various Doppler channels, each representative of a particular radial velocity of the target. Within each channel, the received signals modulated by the first code are matched-filtered by a filter matched to the first code, to produce a first time-compressed pulse, and those modulated by the second code are matched-filtered by a filter matched to the second code, to produce a second time compressed pulse.

Abstract: An angioplasty catheter includes a coaxial transmission line with an elongated center conductor and outer conductor. The transmission line terminates at the distal end in an antenna and a balloon. A longitudinal central bore through the center conductor is dimensioned to accept the guide filament. The center conductor is made from a metallized TEFLON polytetrafluoroethylene fluorocarbon tube.