Abstract: Antenna for operation on a plurality of frequencies, the antenna including apex fed opposing swept elements and a plurality of stubs parallel to a central element, a plurality of capacitors connected between one end of the central element and ends of the stubs, and a coaxial cable connected to the opposing swept elements. Each swept element is of a triangular configuration with a central element running from the apex to the base of the triangle at a substantially perpendicular intersection. A plurality of matching stubs connect from the coaxial fed apex and substantially parallel along the central tube, secured at the other end with clamps or capacitors. Ceramic doorknob capacitors connect between the coaxial fed apex and a free end of the first stub and between the first and second stub ends. A hairpin coil can be utilized between the apex feed and the first capacitor, providing required circuit Q. A matching end can connect across the feedpoint at a common matching stub point for the swept elements.

Abstract: The present disclosure describes an antenna which may be collapsed and stored in a compact configuration and readily released from storage to assume a deployed operative state. More specifically, the antenna is a wire member comprised of a straight section and an integral transverse helical spring section. The antenna lends itself to storage about the axis of a right circular cylinder while permitting full deployment parallel to the longitudinal axis of the latter. This arrangement permits the storage of potential energies of torsion and bending respectively in the helical spring and straight portions of the antenna, and permits continuous motion in these planes to effect antenna erection and deployment.

Abstract: A radar scanner unit for an airborne early warning system comprises an aerodynamic radome pod (1) pivotally mounted on a pylon (2) which is in turn pivotally mounted on a framework (19). The pod (1) can be retracted towards the framework (19) and the unit can be bodily fitted via a standard cargo loading aperture into the fuselage of an aircraft. In flight, the pod (1) can be deployed from and retracted into the aircraft fuselage via the cargo-loading aperture, doors (3) being arranged to fit round the pylon (2) when the pod (1) is deployed.

Abstract: The antenna is designed to radiate decimetric or centimetric waves according to an acute angle .theta..sub.o capable of varying by several dozens of degrees. It has the shape of a rectangular parallelepiped having a thickness e, a length L and a width l.sub.t metal-plated over almost its entire surface and containing a material having a dielectric constant .epsilon..sub.r. According to the invention only a band having a fixed width d has not been metal-plated, which band extends substantially in the center over a large face of the antenna, d being equal to several times e, the second large metal-plate face constituting the ground plane. A micro-strip line (26) which crosses the band and contains the antenna feedpoint (31) electrically interconnects the two metal-plated semi-surfaces (28, 29) defined by the non-plated band. The thickness e is of the order of that of a printed circuit board, the length L (L=N+z.sub.a) is more than twice the wavelength .lambda. of the wave to be transmitted and the width l.sub.

Abstract: This invention relates to a multi-beam antenna and a method of configuring the same, where the antenna consists of a main reflector, a plurality of horns for exciting the main reflector, and separate sub-reflectors for correcting phase errors of respective beams caused by reflection at the main reflector, or an integrated sub-reflector which is substituted for said separated sub-reflectors.

Abstract: Attenuating apparatus is provided for reducing disturbance between transmitting and receiving aerials mounted vertically one above the other. Attenuation is achieved by a grounded screen (1) and a spacer, both mounted between the aerials. The screen is provided with cutouts (6) having a pitch (c) of .lambda./2, where .lambda. is the mean frequency of the pertinent frequency band and .lambda./4 is the depth (d) of the cutouts. The length of the spacer is 0.70.lambda..

Abstract: A frequency independent constant beamwidth lens antenna concept is descri. The device may be configured in various ways such as with a cylindrical lens with a retina. The essential feature is that a twisted planar or hyperbolic paraboloidal phase or wave front is formed by the antenna which then in turn produces a frequency independent constant beamwidth beam in the far field of the antenna. Moreover, the frequency independent constant beamwidth beam may be steered or scanned in azimuth without moving the lens.

Abstract: A retractable motor-driven antenna 10 of compact size and light weight capable of being supported at the top of a support tube 14. A molded plastic housing 12, 30 in part forms the drive motor. A drive transmission 34 for extending and retracting the antenna mast 15 uses a timing belt 78 and pulley wheels 61, 62 and includes an overrunning clutch 84 or energy storage and release interconnection 76 between a drive pulley wheel 261 and a motor output shaft that drives a flexible cord 46 connected to the antenna mast. A switch assembly within the housing includes automatically stops the drive when the mast reaches its extended or retracted position or is obstructed. A coupling between the molded plastic housing and an antenna support tube isolates the housing from road vibration.

Abstract: A low profile antenna structure includes a substantially planar conductive sheet having a substantially planar conductive member extending from one end at a normal angle. A driven radiating element and a parasitic radiating element are disposed adjacent the conductive sheet. A feed point is coupled to the driven element for coupling RF energy to and from the antenna. Both the driven and the parasitic elements are approximately one quarter wavelength long and are approximately parallel to one another and are situated approximately 1/20th of a wavelength apart.

Abstract: A microwave antenna (10) is excited by two independently driven feed lines (30 and 32) so that the plane of polarization of the resultant microwave radiation depends on the relative amplitudes of the signals on the two feed lines. The feed lines are disposed between two parallel ground planes (12 and 14), in one of which is etched an aperture (18). The periphery of the aperture forms ridges (20, 22, 24, and 26) in registration with the feed lines (30 and 32). Conductive eyelets (27) extend between the ground-plane conductors (12 and 14) to act as shorting elements that surround the aperture to form a cavity defined by the shorting elements and the ground-plane conductors. The resultant antenna, which may, for instance, have a thickness of only one-tenth of a wavelength, achieves a 2:1 VSWR bandwidth on the order of 30%.

Abstract: A high-power broadcast television arrangement includes high-power aural and visual carrier sources with rectangular waveguide outputs. A circular waveguide connects the antenna at the top of a tower with the bottom of the tower. In order to avoid an expensive, lossy and complex diplexer for combining the visual and aural carrier signals into a single waveguide, a waveguide turnstile junction couples the visual and aural signals from their respective rectangular waveguides into right- and left-hand circular polarization propagation modes in the circular waveguide. A hollow cylindrical slotted-waveguide antenna at the top of the tower receives the dual-polarized aural and visual signals received from the circular waveguide and radiates a television signal with the aid of resonant radiating slots and polarization-insensitive couplers.

Abstract: A television broadcast antenna includes a high-gain pylon consisting of a vertical array of slots in a conductive cylinder for radiating with high gain towards distant locations. An auxiliary low-gain vertically-polarized portion of the antenna has its phase center coincident with or near the phase center of the pylon for radiating a vertically polarized signal component. This position of the auxiliary portion reduces wind load and feed-line length by comparison with a location above the pylon. In a particularly advantageous embodiment of the invention, the horizontally-polarized radiation pattern of the pylon in the region within a few degrees below the main beam, which is the region directed towards local television viewers, has a low but relatively constant amplitude and phase.

Abstract: A compact, easily manipulable measuring device is provided, particularly useful for properly positioning the feed horn of a parabolic reflector antenna, or the like, relative to the satellite reflecting dish of the antenna. When installing or maintaining an antenna, it is important for optimum signal reception to position the feed horn at or near the focal point of the satellite dish. Such feed horns typically present a central axis, which if aligned with the center point of the satellite dish approximately positions the feed horn at the focal point of the satellite dish. The device of the present invention presents a telescopic rod structure coupled to a support head. The support head presents structure for attachment to the feed horn such that the rod structure preferably lies along the feed horn central axis.

Abstract: A dipole phase shifter for use in a phased array antenna includes an insulating substrate having first and second sides. A dipole element having first and second conductive dipole arms is formed on the first side of the insulating substrate and a PIN/NIP diode pair is mounted on the second side of the insulating substrate and electrically-connected to the first and second dipole arms, respectively. A coaxial RF transmission line having a center conductor extending through the insulating substrate connects an input signal to the phase shifter. Quarter-wave transformers are connected between the center conductor and the diodes to compensate for the forward and reverse bias reactances thereof. The first and second dipole arms serve as groundplanes for the quarter-wave transformers. The center conductor also serves as a common bias line which allows forward biasing of one diode and, simultaneously, reverse biasing of the other diode.

Abstract: A column longeron latch assembly 72 provides the securing mechanism for the deployable, telescoping column 12 of a hoop/column antenna 10. Column 12 is an open lattice structure with three longerons disposed 120.degree. apart as the principle load bearing member and is deployed from a pair of eleven nested bays 22, 23 (FIG. 2) disposed on opposite sides of a center section 21 under the influence of a motor-cable-pulley system (FIGS. 3 and 4). Longeron latch 72 is a four bar linkage mechanism using the over-center principle for automatically locking the longeron sections into position during deployment and serves to unlock the sections when antenna 10 is to be re-stowed. A spring pack 61 disposed in an end of each longeron serves to absorb stress forces on the deployed column through the cam head piston and abutting latch from an adjacent longeron.

Abstract: A reduced height monopole/slot antenna having generally parallel spaced ground planes, the upper one of which has a slot therein, a stripline located between the ground planes, and a monopole extending from the stripline through said slot generally orthogonally through the upper ground plane and being top hat loaded at the outer end thereof. The stripline is offset toward the slotted ground plane, and the slot is capacitively loaded with capacitance connected across the narrow dimension of the slot.

Abstract: The present invention is directed to a multibeam antenna reflector distortion compensation system comprising at least one remote reference radio frequency transmitter cooperating with a feed cluster of a beam forming network which includes one central and at least two peripheral feed elements, means for producing error signals including a circuit for consecutively connecting each peripheral cluster feed element to one input of an adding circuit, and the central feed element to the other input after appropriate attenuation and phase compensation of the central feed signal, and means for down-converting linear and non-linear distortion correction signals based on the down-converter output.

Abstract: A system for in situ heating of oil shale by radiating electromagnetic wave energy from a dipole radiator positioned beneath an overburden in a body of oil shale. Radio frequency power is supplied from the surface through a transmission line to the radiator dipoles whose diameters are substantially greater than the spacing between the transmission line conductors. The dipole radiator is center fed by the transmission line through a reentrant choke structure substantially filled with a solid dielectric medium and concentric with one of said dipole elements.

Abstract: An antenna having more than four elements positioned in a predetermined regular pattern with equal angles between adjacent elements and a mode former connected to the elements to shift signals from the elements by first equal electrical angles and superimposing the signals to provide a first output mode and shifting the signals by second equal electrical angles and superimposing the signals to provide a second output mode, the two output modes providing sufficient information to determine the direction of the radiated signal impinging on the antenna.

Abstract: A low profile antenna comprised of a driven element and a parasitic element spaced above a ground plane. The driven element is connected at one end to the feedpoint of the radio device to which it is attached, the opposite end thereof being free. The parasitic element is connected to the ground plane by its end nearest the feedpoint, the opposite end thereof being free. In the preferred embodiment the parasitic element length and the driven element length are both approximately equal to a quarter wavelength at the operating frequency.