Abstract: A fully collapsible, telescoping asymmetrically loaded half-wavelength vertical antenna. A base of the antenna formed of telescope sections, carries at its upper end an integral, coaxial LC matching network. Coaxially telescoped within the base is a mast formed of multiple telescoping sections, which may be extended and secured in sequence from the ground by an unassisted user. The matching network includes a coil wound concentrically about a form at the upper end of the base, the mast having a lower section telescoped within the coil by a controllable extent for providing preselected capacitance with the base. The upper end of the base serves as the feedpoint.

Abstract: An umbrella type unfoldable antenna reflector net is supported by carrier bs extending radially from a carrier body and by auxiliary ribs extending between adjacent carrier ribs. Bracing wires are connected between the carrier ribs and the auxiliary ribs. The tension of the bracing wires, which in the unfolded state of the reflector net extend substantially in the direction of chords, is adjustable by respective adjustment members so that the bracing tension force has a force component which extends substantially perpendicularly to a plane defined by the unfolded reflector net. The adjustment members permit adjusting the reflector net into a parabolic shape.

Abstract: A radio frequency antenna system is provided comprising: a radio frequency lens having a parallel plate region and having disposed along opposing peripheral portions thereof a plurality of array ports and a plurality of beam ports, such array ports being coupled to an array of antenna elements arranged to provide a plurality of differently, directed relatively narrow collimated beams of radio frequency energy from a common aperture, each one of such beams being associated with a corresponding one of the plurality of beam ports; and, means for coupling radio frequency energy directly into the parallel plate region to provide, from the common aperture, a relatively broad beam of radio frequency energy.In a preferred embodiment of the invention, a plurality of amplifiers is provided, each one of the amplifiers being coupled between an array port and a corresponding one of the antenna elements.

Abstract: A bistatic VHF Doppler radar is utilized to detect and track one or more intruders crossing a large annular ring surveilance zone surrounding a central high security installation. A central omni-directional transmitter radiates the surveillance zone with a continuous wave (CW) signal. Predetermined ones of a plurality of receiver antennas circumferentially spaced around the surveillance zone receive a portion of the signal which is reflected by an intruder crossing the surveillance zone and a portion of the signal which is directly radiated from the transmitter antenna. The reflected signal portion may be received by antenna arrays each of which is controlled to form a null in its pattern toward the transmitter antenna to overcome direct signal overload. The direct signal portion may be received by stub antennas. Each antenna array and each stub antenna is connected to a separate channel of a dual channel receiver.

Abstract: A flat microwave antenna comprising a network of emitting or receiving elements constructed by means of the printed circuit technique on a dielectric support. The elements are arranged on a series of radii (A to H) and are relatively equidistant on each of these radii. In the simplest construction, the radii are equiangularly spaced and the number of elements per radius is equal to 2.sup.n, n being a positive integer proportional to the length of each radial segment.

Abstract: Support structure for a paraboloid reflector of electromagnetic radiation. The structure comprises a plurality of abutting flat ribs arranged on edge in rotated concentric square patterns, with the ends of inner ribs meeting the sides of adjacent outer squares at forty-five-degree angles. The concave parabolic forward edges of the ribs are aligned at their junctures, establishing the curve of a screen reflector. Corner gussets are positioned on parallel planes that are perpendicular to the focal axis of the paraboloid. The structure is assembled by inserting fasteners through matching holes in the ribs and corner gussets.

Abstract: In a slotted array antenna (12), an asymmetric ridge waveguide element (13) defining colliner radiating slots (16), said waveguide elements (13) defining a central hollow region (13') and an axial ridge (13") separating first and second series of side chambers (17' and 17") alternating in height with respect to each other, whereby production of second order beams of radiation from said antenna (12) is eliminated and much lower side lobe levels are produced when the element (13) is used in an array scanned in a plane perpendicular to the element axes.

Abstract: An angular filter for electromagnetic radiation is formed of a set of elements supported on a dielectric substrate. The elements are electrically conducting and include resistance for dissipating energy of the radiation. Each element is formed as a closed loop in a plane normal to an axis of propagation of the radiation so as to minimize interaction with a transverse magnetic field of the radiation at zero angle of incidence to the filter, the interaction and consequent attenuation increasing with increasing angle of incidence. Thereby, spurious sidelobes of a radiation pattern associated with a radar or other antenna can be reduced by the filter in favor of the main lobe along the antenna axis. The elements may be formed by a set of members spaced apart to introduce capacitance for resonating with inherent inductance of the members, thereby to enhance the filter attenuation.

Abstract: The multiple feed antenna comprises a primary focussing element and at least two feeds. The feeds are spaced from each other and have different characteristics such as different frequency bands. The focussing element is moved such that its focal point coincides individually with the feeds. The focussing element may be designed to be offset with respect to its focal axis. In this manner, the antenna may have a common aperture and common boresight for each of the feeds.

Abstract: A dual mode antenna that allows both millimeter wave radiated energy and rared radiated energy to enter a single aperture and propagate through a common transmission device to a point where the respective energies are divided to follow separate paths for subsequent processing. An electromagnetic transmission guide for waveguide comprises first and second parallel tubular members having beam directing reflectors and lenses therein for maintaining low-loss, gaussian beam propagation of radiated energy therethrough. Cassegrainian optics of a cassegrainian antenna system are positioned for directing the millimeter and infrared energy into a common, circular end of said tubes where the energy impinges on beam directing means that separates the respective energies, directing them into the respective parallel tubes along two separate and distinct paths.

Abstract: An apparatus for rotating and driving an antenna device in a radio transmitter and receiver which can simply increase and decrease the driving torque by variation in weight thereof. This apparatus comprises a rotary body rotatably mounted on a main housing and supporting the antenna device thereabove, and one or more driving units detachably mounted on the main housing. The rotary body is connected to an input gear rotatably provided on the main housing through a gear mechanism. Each of driving units has a driving source and a keyway gear connected through the gear mechanism, the keyway gear being meshed with the input gear when the driving unit is mounted on the main housing. Thereby, the driving torque required for rotation of the antenna device is adjusted by increase or decrease in number of the driving units.

Abstract: A microwave lens broadens the radiation pattern of an antenna feedhorn so as to result in improved illumination of the reflector surface. The lens, constructed of dielectric material in the shape of a half-torus, provides feed radiation patterns suitable for use with deep paraboloidal reflectors, typically ones having focal-length-to-diameter ratios between 0.25 and 0.35.

Abstract: The problem of recurrent solder joint failure in spiral antennas is solved by the present invention through the use of resistive/capacitive contacts. Specifically, an electrical connector is provided for connecting opposed conductors disposed on a stripline, to a spiral antenna having a pair of dipole conductors disposed on a substrate. The connector includes a housing having a base, and a sidewall for supporting the substrate. A center post having first and second ends, and a cylindrical aperture, is mounted in the housing. The substrate is secured to the first end of the center post, the second end thereof secured to the base of the housing. A stripline contact snubber is supported in an end of the cylindrical aperture adjacent the substrate and receives the stripline. To ensure RF continuity between the stripline conductors and the dipole conductors, one or more mechanically compliant, leaf spring resistive/capacitive contacts are provided.

Abstract: Antenna structure 10 has a primary reflective surface 12 over which is positioned a subreflector surface 14. Support webs 32, 34 and 36 are made of low dielectric loss insulating material and are adhesively secured in slots in the reflectors. The support webs are positioned on planes through the axis so that the small thickness of the webs is in the projected area and results in an unobstructed and undistorted electromagnetic radiation pattern. The webs firmly support the subreflector in the desired position. The antenna can be configured as a Gregorian system as shown or alternatively as a Cassegrainian system.

Abstract: A dual mode broad band antenna especially designed to provide simultaneously high and low angle radiation patterns relative to a horizontal ground plane is disclosed herein. This particular antenna utilizes four wire radiators in the form of an inverted conical log-spiral supported in a vertically extending fashion a predetermined distance above the horizontal ground plane. In order to operate the antenna in its high and low angle modes simultaneously, first and second oppositely phased AC currents are applied to the radiators in two different ways through specifically connected hybrid isolating transformers.

Abstract: The antenna of the invention is suitable for use with an aircraft and is capable of receiving a plurality of frequency ranges in the communication band and provides a directional antenna. To this end there is provided an upper wing element from which extend vertically two outer leg elements and a central leg element. The central leg element extends into a fairing disposed below and substantially coextensive with the wing element. Two symmetrical slots are disposed in the wing element symmetrically disposed about the central axis. Another slot extends through the central leg element and the fairing. The slots are provided with capacitors to provide antiresonant circuits at predetermined frequency ranges.

Abstract: An FM antenna for use with a radio receiver which features plural, elongate open loop reception elements which are mutually coupled to one another. These elements may be equidistantly arranged about and spaced from an axis generally parallel with the element sides. The antenna is particularly effective for receiving weak and/or distant FM signals.

Abstract: A transceiver element for controlling the phase of a microwave signal passing therethrough. The transceiver element includes a plurality of switching means arranged to steer a microwave frequency signal provided by a radar system through a nonreciprocal phase shifter to a phased array antenna during a transmit mode, and to steer a microwave frequency signal received by the phased array antenna through the nonreciprocal phase shifter to the radar system during a receive mode. The microwave frequency signal passes through the phase shifter in the same direction during both the transmit and receive modes. A set of control signals is fed to such switching means and the phase shifter of the transceiver element to provide collimated and directed beams of microwave energy during the transmit mode and the receive mode.

Abstract: A deployable spacecraft borne circular reflector structure comprises a plurality of plies of graphite fiber reinforced epoxy (GFRE) fibers, each ply comprising at least two layers of graphite epoxy reinforced fibers having quasi-isotropic properties. A circular ring of multiple layer plies of like construction as the reflector and having a U-shaped cross-section is bonded to the reflector rear surface adjacent the reflector peripheral edge. Each layer of each structure is formed from prepreg graphite fiber epoxy reinforced material.

Abstract: A retractable airborne radar pod housing a radar scanner is provided with inflatable portions which when deflated allow the pod to be retracted into the aircraft and when inflated form an aerodynamic shape.