Abstract: A microwave antenna comprising the combination of a paraboloidal main reflector; a subreflector located such that the paraboloidal main reflector and the subreflector have a common focal point lying between the main reflector and the subreflector; a feed horn for transmitting microwave radiation (preferably symmetrically) to, and receiving microwave radiation from, said subreflector; and a shield connected to the peripheral portion of the subreflector and having an absorbing surface which reduces side lobe levels both by capturing the feed horn spillover energy and by reducing the diffraction of microwave radiation from the edge of the subreflector. The shield is preferably formed as a continuous axial projection extending from the periphery of the subreflector toward the main reflector substantially parallel to the axis of the feed horn. The reflective surface of the subreflector is suitably a section of an approximate ellipse.

Abstract: A dual gridded antenna reflector system and method for constructing the same is disclosed. The reflector system comprises a pair of reflector dishes each having a grid of parallel conductors. One of the reflector dishes is mounted over the other reflector dish by linear support ribs therebetween such that the conductors of the one reflector dish are perpendicular to the conductor of the other reflector dish. The linear support ribs are placed perpendicular to or parallel to the conductors of the overlapped reflector and are placed substantially outside of the high field region across the aperture of the overlapped reflector.

Abstract: An antenna having an antenna aperture area and an antenna reactance comprises a first antenna element (31) defining a first aperture area and a first reactance and a second antenna element (32) connected in parallel to the first antenna element to put a miniature radio receiver into operation in a desired frequency band. The second antenna element has a second aperture area and a second reactance greater than the first aperture area and reactance, respectively, so that the antenna aperture area and reactance are substantially determined by the second aperture area and the first reactance, respectively. The first and the second aperture areas may be coplanar. Alternatively, the aperture areas may be orthogonal to each other.

Abstract: Antenna mount comprised of an essentially tubular length of an elastomer, to which, at one end, a fitting adapted to receiver an antenna is secured and, at the other, a fitting adapted to receive a lead-in connector is also secured. A flexible conductor extends between the portions in the fittings where electrical contact is made with, respectively, the antenna and a coupler for the lead-in to the radio set. Noise-free duplexing can be obtained.

Abstract: A dual band array antenna is disclosed having interleaved waveguide and dipole arrays, each operating in a different frequency band. The orientation of the waveguides and dipoles is such that polarization of the signals of the two frequency bands is perpendicular to each other, thus reducing mutual coupling. The waveguides are used for the higher frequency band and their cutoff frequency is selected to be above the lower frequency band at which the dipoles operate, in order to reduce mutual coupling into the waveguides. In one embodiment the dipoles are printed on a substrate having a dielectric constant selected so that dipole spacing is the same as the waveguide spacing. This eliminates grating lobe formation in the radiation pattern of the waveguide array. A low pass filter is included in the dipole feed circuit to reject the frequencies at which the waveguides operate.

Abstract: A microstrip antenna comprises a first dielectric layer having a permittivity of 2.5-12.5 carrying the ground plane on one face and a feeder-resonator on the opposite face; a second dielectric layer thereover having a permittivity of 2.2-2.5 and carrying on its outer face a radiator electromagnetically coupled to the feeder-resonator; and spacing means spacing the second dielectric layer from the first a distance of up to seven times the thickness of the first, and providing a permittivity between the two dielectric layers which is approximately that of air. Matching of the antenna is obtained by varying the spacing between the two dielectric layers. The gain of the radiating element is better than 7.5 dbi for bandwidth of 15%. Sidelobe level is less than 15 dB in azimuth and elevation plan. The radiation pattern of the antenna is symmetric in both azimuth and elevation plan.

Abstract: A technique for reducing cross-polarized signals in the axis of four-port al-polarized antennas. The resulting lower cross-polarized signals reduce a tracking antenna's susceptibility to tracking errors and to breaklocks. Some energy from the transmission line connected to the (V) port is coupled, after proper attenuation and phase adjustment, and transmitted through the (H) port, thereby nulling out the (V) cross-polarized pattern.

Abstract: A compact lightweight flexible omnidirectional broadband UHF antenna of the fat monopole type is disclosed. The antenna comprises a braided copper sleeve molded inside a truncated cone of neoprene rubber. The antenna is suitable for vehicle or mast mounting. When mast mounted, the antenna may be associated with ground plane rods, each of which is mounted to a common support by means of a pivot with yieldable protuberances. The protuberances yield to the plane face of the support and will, therefore, enter recesses provided in the support in the rotational path of the protuberances. When the protuberances enter the recesses, the associated ground plane rod is locked in either an operational or a storage position.

Abstract: The antenna feed includes a waveguide radiator with a conductive flange positioned about the waveguide near its radiating end. The flange includes one or more corrugations which each have tapered walls and which is truncated at its root and crest by a flat or curved plane. The corrugations thus may have a trapezoidal cross-section or a curved root and crest cross-section. The curvature may be sinusoidal.

Abstract: An electrically small, efficient electromagnetic structure, that may be used as an antenna or waveguide probe, having an electromagnetically closed, velocity-inhibiting conducting path, for supporting a standing, inhibited-velocity wave in response to the flow of an electrical current through the path and a process for establishing the standing wave. Use of the structure is particularly advantageous at the lower end of the electromagnetic spectrum, where various embodiments produce purely vertically polarized radiation in directional and omnidirectional patterns. Various embodiments of the structure include multiple conducting paths and image means to complete the conducting path.

Abstract: Emitting and receiving antenna system for accommodating all bands and frequencies and for operating selectively adjustably in resonance at a given emitting or receiving frequency, formed by one antenna component or two counterpart antenna components, each component containing therewithin a variable inductor and a variable capacitor, a drive mechanism for shifting the shiftable inductor part relative to the fixed inductor part of each such inductor for varying the inductance and conjointly for shifting the shiftable capacitor part relative to the fixed capacitor part of each such capacitor for varying the capacitance, and a control mechanism for controlling the drive mechanism for selectively shifting the corresponding shiftable parts conjointly for achieving selective antenna resonance tuning at an exact point corresponding to the desired operating band and frequency, such as with the shiftable inductor part and shiftable capacitor part of each antenna component being connected together for common shifting mo

Abstract: The present invention relates to a scanning beam antenna comprising a doubly-curved main reflector, a doubly-curved subreflector and at least one linear array feed. The main reflector is doubly-curved in two planes to produce a separate first focus for each feed in a first plane in front of the subreflector and a separate second focus for each feed in a second orthogonal plane behind the subreflector. The subreflector is curved to refocus each second focus of the main reflector to coincide with the image line of a first axis on the reflecting surface of the main reflector in the first plane. Each feed array is disposed at a separate secondary focus of the combination of the main reflector and subreflector. The resulting antenna provides very little phase error due to aberrations as each beam is linearly scanned.

Abstract: An antenna system in which primary radiators are disposed on the radiation side of beams from a main reflector and in opposition to a subreflector and in which the subreflector and the primary radiators are disposed in positions offset from beam blocking positions.

Abstract: A dielectric trough waveguide antenna composed of a metallic guide having a dielectric substrate covering the bottom of the guide and a plurality metal radiators placed periodically on the dielectric at the dielectric-air interface provides a low loss antenna suitable for millimeter wave applications.

Abstract: A method for obtaining a linear cellular array employing cosine-squared antenna patterns is disclosed. The array herein described provides an essentially infinite linear band of coverage utilizing only six frequencies. The embodiment of this invention provides early frequency reuse and superior co-channel interference to existing cellular systems used today. An alternate embodiment provides total area coverage along selected portions or the entire linear band of cellular coverage.

Abstract: The invention relates to a loop antenna tuned by means of a variable capacitor.The antenna includes, in parallel with the variable capacitor (4), a switchable state variable inductor (11).The invention is particularly applicable to antennas for HF radio links at powers of up to 1 kW.

Abstract: A motor-driven adjustable mounting structure for satellite T.V. dish antennae which operates to scan an in line of sight segment of a geostationary T.V. relay satellite orbit belt. The mounting structure includes a vertical mounting post, a universal levelling structure atop the post, a vertically extending body pivotally carried by the levelling structure on a horizontal axis, a head structure rotatably carried by and projecting upwardly from the body and including an antenna carrier structure carrying the antenna with its axis normal to the vertical axis of the body and turning axis of the head.

Abstract: A log periodic antenna (1) comprising two substantially identical non-resonant elongated log periodic conductive zig zag structures (3,5). The structures (3, 5) lie side-by-side in close proximity to each other in substantially the same plane defined by a planar dielectric board (13). The zig zag structures (3, 5) are axisymmetric about a line of symmetry coinciding with the midline of an impedance matching feed line (18). The feed line (18) comprises two substantially identical elongated conductive members (7, 9), sandwiched around the dielectric (13). The first zig zag structure (3) and the first member (7) lie on one side of the dielectric board (13), while the second zig zag structure (5) and the second member (9) lie on the other side of the board (13). At microwave frequencies, the zig zag structures (3, 5) and the member (7, 9) are preferably mounted on the dielectric board (13) using printed circuit techniques.

Abstract: A planar high-frequency antenna having radiating elements for high-frequency signals includes at least two facing conductive plates provided with oppositely-arranged openings which cooperate to form respective cavities. Disposed between each pair of facing plates is a thin dielectric sheet supporting an array of strip conductors of coaxial lines forming suspended-substrate microstrip lines with these plates. Ends of the strip conductors extend into the cavities and form radiating elements. Each thin dielectric sheet is held in place between the facing plates by means of positioning spacers provided on the faces of these plates. The spacers are located in areas where there are no conductors on the dielectric sheet and are sufficiently remote from each other such that at least two cavities and/or lines of the network of strip conductors are located between any two spacers.

Abstract: An antenna reflector structure of the offset-fed type which is suitable for use on spacecraft. The reflector structure includes a central boom, a number of spaced ribs on the boom, an RF reflective mesh layer adjacent to the outer, transverse peripheral edges of the ribs, and contoured angle members for securing the mesh layer to the ribs to provide a specific contour for the reflector surface defined by the mesh layer. The boom can be of one-piece construction or formed from telescoped segments. The reflector structure is deployable and furlable. Several embodiments of the reflector structure are disclosed.