Abstract: When a converter 14 is rotated via a rotation mechanism 17, the arrangement inclination angle of two primary radiators 15a and 15b can be adjusted in the range of 0 to 20 deg. with respect to an axis which is in parallel with the ground. Also the reception polarization angle due to probes of the primary radiators 15a and 15b can be adjusted in the range of 0 to 20 deg. while maintaining a preset difference in polarization angle among the satellites. Therefore, the arrangement inclination angle of the primary radiators 15a and 15b for respectively receiving signals from the two satellites, and the reception polarization angle in the primary radiators 15a and 15b can be simultaneously easily adjusted by rotating the converter 14 via the rotation mechanism 17.

Abstract: This invention is a compact and cost effective multiple-feed signal receiver for use in conjunction with a parabolic dish antenna to receive electromagnetic signals from more than one satellite clusters. The multiple-feed signal receiver has a multi-layer structure to integrate circuit boards for different frequency bands or the same frequency band for different signal processing within a limited cross-section and to isolate these boards from signal interference with one another.

Abstract: An omnidirectional microwave antenna comprises a paraboloidal reflector disposed above the ground and facing downwardly with a substantially horizontal aperture and a substantially vertical axis. A vertically oriented feed horn is located below the paraboloidal reflector on the axis of the paraboloidal reflector and has a phase center located near the focal point of the paraboloidal reflector. A conical reflector having a shaped reflecting surface defined by the parameters of a mathematical equation extends downwardly away from the periphery of the feed horn for reflecting radiation received vertically from the paraboloidal reflector in a horizontal direction away from the conical reflector, and for reflecting horizontally received radiation vertically to the paraboloidal reflector.

Abstract: An improved dual gridded reflector antenna configuration which allows cross-polarization radiation to be scanned in any given direction. The dual-gridded reflector assembly includes a front parabolic reflector illuminated by a first source, and a second parabolic reflector illuminated by a second source. The second reflector is positioned adjacent to and behind the front reflector such that the center points of the reflectors align to define a center axis. Additionally, the first and second sources are positioned at different offsets with respect to the reflectors and have a respective rotated offset angle with respect to the center axis such that the sources define an antenna feed separation. By modifying the offsets and the rotated offset angles, the feed separation can be designed to have an inclination with respect to the north-south or east-west feed separation direction.

Abstract: When a converter 14 is rotated via a rotation mechanism 17, the arrangement inclination angle of two primary radiators 15a and 15b can be adjusted in the range of 0 to 20 deg. with respect to an axis which is in parallel with the ground. Also the reception polarization angle due to probes of the primary radiators 15a and 15b can be adjusted in the range of 0 to 20 deg. while maintaining a preset difference in polarization angle among the satellites. Therefore, the arrangement inclination angle of the primary radiators 15a and 15b for respectively receiving signals from the two satellites, and the reception polarization angle in the primary radiators 15a and 15b can be simultaneously easily adjusted by rotating the converter 14 via the rotation mechanism 17.

Abstract: An antenna system having a front reflector and a rear reflector arranged in tandem, a front feed for illuminating the front reflector, and a rear feed for illuminating the rear reflector. Each of the reflectors has a generally dish-shaped configuration, and the feeds are located in positions offset from axes of the respective reflectors. The front reflector is reflective to a first radiation, while being substantially transparent to a second radiation except for a fraction of the power of the second radiation. The fractional part of the second radiation is reflected from the first reflector as an interfering beam, the interfering beam being scanned away from a coverage region of a beam of the first radiation by an offset between the feeds. The radiations may differ in polarization or in frequency.

Abstract: A unit for combining N channel signals produced by N respective separate sources, where N is an integer, comprises a collector array receiving the N channel signals in respective directions defined by array lobes associated with the collector array.

Abstract: A single radiating structure with an integrated mode transducer that produces near-ideal radiation characteristics at two frequency bands. The dual band feed consists of three main sections: feed waveguide, mode transducer and corrugated horn. The feed waveguide consists of two concentric, circular waveguides that are excited in the TE.sub.11 coaxial and circular waveguide modes for the low and high bands, respectively. The mode transducer, which is critical to the performance of the feed, provides a single mode, low return loss transition, for both bands, between the feed waveguide and the corrugated horn. This is achieved by converting the TE.sub.11 circular waveguide modes into the fundamental hybrid, HE.sub.11, mode of the corrugated horn. The corrugated horn, which is a stepped-slot configuration, is designed to achieve a smooth transition from the mode transducer and to produce the desired radiation characteristics at both frequency bands.

Abstract: A dual mode horn reflector antenna for providing an antenna pattern having symmetrical beamwidths over a bandwidth of approximately 40%. An input TE.sub.10 rectangular mode signal is provided to the dual mode horn reflector antenna which generates a first TE.sub.11 circular mode signal from the input TE.sub.10 rectangular mode signal. A first TE.sub.10 square mode signal and a first TE.sub.01 square mode signal are generated from the first TE.sub.11 circular mode signal. The first TE.sub.10 square mode signal and the first TE.sub.01 square mode signal are combined generate a resultant signal. The resultant signal is incident upon a reflecting structure which generates an antenna pattern having approximately equivalent beamwidths in perpendicular planes, and reduced sidelobes.

Abstract: An improved subreflector antenna with lower sidelobes than prior art subreflector antennas is disclosed herein. A tapered, anisotropic, corrugated subreflector is attached to a waveguide and located at the focus of a near-parabolic deep dish main reflector. The subreflector has corrugations of varying depth. The varying depths of the corrugations result in varying reactance, or reactance taper, of the subreflector. This taper is designed in such a manner to guide or steer the energy from the antenna feed to the main reflector in such a manner as to help assure sharply reduced sidelobes. Further, the subreflector is physically shaped so as to further steer or guide the energy in the desired direction. The deep geometry of the main reflector allows the reduced sized subreflector to be positioned within the rim of the main reflector such that the combination can be covered by a flat radome.

Abstract: A feed assembly waveguide interface (10) between an antenna (12) coupled onto an upright post (14) and an outdoor radio (16), comprising a feed tube (18) connected at a first end (20) to a sub-reflector (22) and a second end (24) having a waveguide output (26). A structure (28) is for affixing the feed tube (18) internally within the antenna (12), so that the second end (24) will extend outwardly from a rear wall (30) of the antenna (12). An assembly (32) for spring loading the feed tube (18) on the affixing structure (28) will allow the second end (24) to be forced outwardly away from the rear wall (30) of the antenna (12). When the outdoor radio (16) is mounted to the rear wall (30) of the antenna (12), a positive interface connection will be made between the outdoor radio (16) and the antenna (12), thus making a solid mechanical connection between the outdoor radio (16) and the antenna (12), as well as a proper electrical and environmental seal.

Abstract: Systems and methods for two dimensional millimeter wave imaging are described. A system includes a spindle assembly defining a rotation axis; a waveguide assembly connected to the spindle assembly, the waveguide assembly including a first dielectric waveguide defining a first axis; and a grating assembly connected to the spindle assembly, the grating assembly including a plurality of sectors, each of the plurality of sectors including a varying period conductive grating pattern. A varying period of the varying period conductive grating pattern is a function of an angle defined by a rotational position of the grating assembly with regard to the rotation axis. The systems and methods provide advantages in that an image can be scanned quickly using an inexpensive system.

Abstract: An excitation system is indicated for an antenna with a parabolic reflector (1) and a dielectric radiator (3) which is attached to the end of a hollow conductor used to guide electromagnetic waves, and is located in the center of the reflector (1) and has a metallized end face designed as a subreflector. The reflector (1) is designed as a rectangular strip forming a sector antenna which has a parabolic curve in the direction of its long axis (A). The end face of the radiator (3) has four partial faces (8, 9, 10, 11) which form pairs and are arranged with respect to the central axis of the hollow waveguide (2) so that each pair of partial faces extends approximately at a right angle to the other pair of partial faces, the partial faces of each pair being of equal size. The two partial faces (8, 9) extending in the direction of the long axis of reflector (1) are large in relation to the two partial faces (10, 11) extending crosswise thereto.

Abstract: A device is indicated for covering the aperture of an antenna having a parabolic reflector and an exciter. The cover is made of a rigid material. The cover includes a shield ring connected to the reflector and a plastic cover shaped like a flat or obtuse cone having a conical portion which closes the open end of the reflector. The wall of the conical portion of the cover forms an angle between 4.degree. and 6.degree. with a plane that is at a right angle to the axis of the shield ring.

Abstract: A steerable feeder link antenna is formed of a steerable reflector and a stationary feed horn assembly. A novel feed horn assembly allows dual mode transmit and receive functions for circularly polarized microwaves. The feed horn assembly includes a four arm turnstile junction coupled to a feed horn through the feed horn's side wall to couple transmit frequencies and an axially coupled transmission line for the receive frequencies. Each turnstile junction arm incorporates chokes for the receive frequencies. The transmission line's cut off frequency is above the transmit frequency to prevent transmit signals from interfering with receive signal receivers.

Abstract: A feed structure for transmitting or receiving microwave energy to or from a reflector includes a waveguide having an input section, intermediate section, and output section. The waveguide has an inner surface of generally rectangular cross section and an outer surface of generally circular cross section. The outer surface includes unique opposing convex surfaces which enables the waveguide to be bent with minimal resulting deformation of the internal rectangular surface. At least one locating surface is provided on the outer surface of the waveguide for determining the orientation of the waveguide. The input section of the waveguide has a threaded cylindrical surface adapted to be connected to a hub having a threaded interior bore which is connected to the reflector. A feed horn integral with the output section of the waveguide and having a circular output aperture is formed by machining the inner surface of the waveguide into a rectangular to circular transition.

Abstract: An antenna device has a plurality of radar modules having respective integrated circuit boards of transmitter and receiver circuits for transmitting and receiving electromagnetic waves and a common case or respective case members accommodating the integrated circuit boards. The common case or case members have respective primary radiators integrally formed therein. The primary radiators are positioned at the focal point of an offset reflector which is fixedly supported by a holder 10 that also supports the radar modules.

Abstract: A rear feed source for a reflector antenna and an antenna using such a source. The source includes at least one horn connected to a waveguide. The horn has at least two inclined walls forming an aperture, each wall being extended by a wall with a different inclination. This invention can be applied to radars, notably surveillance radars.

Abstract: A scanning antenna is disclosed including: a rotatable cylinder having an outer surface; a continuously, or steppingly, varying period conductive grating pattern of separated strips on the outer surface, the varying conductive grating pattern of separated strips defining a grating axis; and a first elongated dielectric waveguide defining a first waveguide axis, the first elongated dielectric waveguide being located proximally adjacent and alongside the varying conductive grating pattern of separated strips so as to evanescently couple electromagnetic signals with the first elongated dielectric waveguide. The scanning antenna provides advantages in that the gain is high.

Abstract: A siamese feedhorn for a satellite receiving antenna capable of simultaneously receiving signals from satellites in different geostationary satellite positions. The siamese feedhorn preferably includes a first waveguide section mated with a second waveguide section. The first waveguide section is preferably positioned at the antenna's focal point to receive signals from within the antenna's beamwidth. The second waveguide section is positioned at an offset distance from the focal point to receive signals from a satellite in a different geostationary position.

Abstract: The satellite communications terminal employs separate transmit and receive feedhorns, offset from one another, to achieve adequate isolation of received and transmitted signals during full duplex operation. In one implementation, described herein, the satellite communications terminal employs an ultra-small-aperture dish antenna having an aperture of about one meter. Signals are received and transmitted at Ku band wavelengths of about 12 gigahertz and 14 gigahertz respectively. For this implementation, an extended focal point zone occurs, rather than a discrete focal point. Both the receive and transmit feedhorns are positioned within the focal point zone thereby achieving adequate gain to both reception and transmission. However, the receive and transmit feedhorns are offset from one another to minimize the coupling of feedback transmission signals into the receive feedhorn.

Abstract: A feed structure for an antenna, comprising a feed horn having an input end and an output end, a collar threadably engaged to the output end of the feed horn and a protective window interposed between the feed horn and the collar. The collar forms an aperture exposing said window.

Abstract: A data transmitting/receiving satellite terminal for transmitting to and receiving from a geosynchronous satellite employs an antenna having nulls in its antenna receiving pattern at a first frequency corresponding to satellites spaced at regular intervals from the satellite. In addition, a phase and amplitude compensation network adjusts a phase and amplitude of the transmitted signal to compensate for transmitting at a different frequency than for which the antenna is optimally designed. The antenna includes a main parabolic reflector, and two side parabolic reflectors offset from a plane parallel to the main parabolic reflector. Each of the reflectors uses a dual frequency feed horn to couple energy to and from the reflector to a dipole exciter to which the receiving electronics is coupled. The above terminal is particularly useful in C-Band applications.

Abstract: A feedome is disposed on the side of an opening of a radiator main body, and comprises a dielectric board having a thickness sufficiently smaller than the wavelength of radio wave, and a dielectric protrusion fixedly mounted to the dielectric board substantially in the center of the inner side thereof, and having a height approximately equal to integral number times (1/2).multidot..lambda. where the wavelength of radio wave is .lambda., and a diameter approximately equal to the height of the dielectric protrusion.

Abstract: An antenna suitable for use at subscriber sites in a television distribution system having a high front-to-back ratio and optimized for reception within multiple frequency bands. The antenna is comprised of multiple tapered antenna stages including a primary antenna stage for receiving a primary frequency band and a coupling antenna stage for matching the impedance of the primary antenna stage to either a coaxial cable or downconverter electronics. The multiple antenna stages are alternatively formed from either a stamping of a metal sheet or a double sided printed circuit board.

Abstract: An elliptic beam antenna easy to design and simple in structure. To generate elliptic beams of about the same size regardless of the kind of polarized waves for excitation, a horn antenna or waveguide structure intended for radiating out radio waves into space features the provision of diamond aperture, modified from the conventional circular, elliptical, square or rectangular one and excitation of radio waves in diagonal directions.

Abstract: Multiple shaped-beam or scanned beams reflector or lens antenna configured so as to have the radiating elements outside the focal plane (imaging) with improved characteristics in terms of gain and coverage area. Said antenna (FIG. 1) essentially consists of a reflector or a lens (1), a certain number of radiators (3) positioned outside the focal plane, a Beam Forming Network (BFN). It classifies in the technical field of multiple shaped-beam antennae and is applicable to radars, telecommunications in general and to space telecommunications in particular. Its most significant advantage consists in its use as transmitter antenna since in it the electric performance/complexity ratio is improved.

Abstract: A reflector antenna assembly for dual linear polarization includes at least two feeds and two reflectors. At least one reflector has a surface which is nominally electrically transparent to linearly polarized radiation in one direction and is located in front of the other reflector so as to be closer to said feeds. At least one of the reflectors is profiled in a manner such as to enable it to generate at least one complex contoured beam while using one of said feeds.

Abstract: Compact, microwave scanned antennas include combinations of a radiator, a reflector and a mirror. The radiator is formed by plating a shaped dielectric core. It generates an antenna beam at an output aperture in response to a microwave signal at an input port. The wavefront orientation of the antenna beam is a function of the wavefront orientation of the microwave signal at the input port. Changing the angular relationship between the path of the microwave signal and the input port changes the wavefront orentation of the antenna beam and, therefore, its beam axis. Pivoting the reflector realizes the desired angular change in the microwave signal path. Alternatively, the reflector can be fixed and the mirror pivoted to vary the microwave signal path. Antenna embodiments can be physically realized with a single moving part, the shaped dielectric is easy to form and when configured to operate at a high frequency, e.g., 77 GHz, the antenna is small enough to fit behind an automobile license plate.

Abstract: A scanning antenna is disclosed including: a rotatable cylinder having an outer surface; a varying period conductive grating pattern of separated strips on the outer surface, the varying conductive grating pattern of separated strips defining a grating axis; and a first elongated dielectric waveguide defining a first waveguide axis, the first elongated dielectric waveguide being located proximally adjacent and alongside the varying conductive grating pattern of separated strips so as to evanescently couple electromagnetic signals with the first elongated dielectric waveguide. The scanning antenna provides advantages in that the gain is high.

Abstract: An antenna for inertialess scanning a beam through 360 degrees or any desired sector thereof. A reflector, in the shape of a truncated cone that is tangential to an imaginary sphere in the central plane of the cone, is positioned above a feed array located in the equatorial plane of the sphere. The feed array is fed by a network with a plurality of input ports, each of which corresponds to a beam in space. By successively energizing these input ports the beam is caused to scan continuously over the desired sector.

Abstract: A dual-reflector antenna system (40) is provided for generating a shaped main beam radiation pattern (20) and at least one additional secondary spot beam radiation pattern (30,32). The antenna system (40) includes a main shaped reflector (10) having a shaped reflective surface (11) operatively coupled to a subreflector (12) for communicating therewith. A main feed horn (14) communicates directly with the subreflector (12) so as to reflect first energy to and from the main reflector (10) within a shaped beam radiation pattern (20). In a preferred embodiment, the subreflector (12) has an ellipsoidal reflective surface (13) which communicates directly with the main reflector (10) via an inverted reflective path (17) which has a converging focal point (18). One or more auxiliary feed horns (24,26) are operatively coupled directly to the main reflector so as to directly communicate therewith and reflect second energy within one or more additional radiation patterns (30,32).

Abstract: A dielectric body 20 with a dielectric constant near that of air has a surface 18, a portion of a paraboloid of revolution about an axis 9--9. A layer 15 of electrically conducting material is shaped by surface 18 to the form of an antenna reflector for transmitting electromagnetic radiation, or for receiving electromagnetic radiation indicated by arrows 50. A mating body 30 covers conductive layer 15. Dielectric body 20 has a protrusion 17 that mates with a horn 40 at a specified position relative to conductive layer 15, with horn axis 8--8 perpendicular to paraboloid axis 9--9.

Abstract: An omnidirectional microwave antenna comprises a conical reflector and a conical feed horn. The conical reflector has a reflecting surface defined by a cone having an axis and a surface of revolution around the axis. The line of intersection between the surface of revolution and a plane passing through the axis and the surface of revolution is a segment of a parabolic curve. The reflector includes a flange extending outward from an outermost circumference of the surface of revolution of the cone. The conical feed horn feeds microwave energy to the conical reflector from a location along the axis of the cone. The feed horn has an aperture whose center is located approximately at the apex of the cone. The flange has absorptive material mounted thereto for absorbing microwave energy impinging thereon.

Abstract: A mechanism for mounting a receiving/transmitting horn in a satellite dish includes a casing for supporting the horn and for shielding the coaxial cable connectors and a low noise block from rain, snow, wind and the sun. The casing includes a recessed portion arranged at an angle with respect to the longitudinal axis of the casing. The recessed portion slides into a feed-arm in a weatherproof manner. The longitudinal axis of the feed-arm is offset from the axis of the satellite dish. The casing, feed-arm, angle and horn support are dimensioned to optimally position the horn at the focal point of the parabolic dish.

Abstract: A parabolic-reflector antenna having a primary horn including first, second, and third hollow portions. The first hollow portion has an elliptical aperture on one end thereof and a circular cross section on an opposite end thereof, and is progressively tapered away from the elliptical aperture. The second hollow portion has a circular cross section and a constant diameter, and is joined to the opposite end of the first hollow portion. The third hollow portion has a circular cross section on one end thereof and a circular cross section on an opposite end thereof. The third hollow portion is joined to the opposite end of the second hollow portion, and is progressively tapered away from the second hollow portion. The parabolic-reflector antenna also includes a parabolic reflector having an elliptical aperture whose major axis is perpendicular to the major axis of the elliptical aperture of the primary horn.

Abstract: A microwave antenna has a circular wave guide feedhorn mounted above a reflector. An electrically insulating sleeve fits around the outer diameter of circular wave guide. A scalar ring is secured to the insulating sleeve. The sleeve isolates the ground of the circular wave guide from the reflector and scalar ring so that electrostatic charge accumulating in the reflector does not damage electronic components electrically coupled to the wave guide.

Abstract: A multibeam antenna for simultaneously receiving waves from one or more communication satellites and a broadcast satellite, which are apart in their stationary orbit positions over the equator, is disclosed. The antenna employs an offset parabolic face, used as a reflector for receiving satellite broadcast waves, a converter having a primary radiator for receiving communication satellite Waves set at the focus point of the offset parabolic face, and a converter having a primary radiator for receiving broadcast satellite waves set near the envelope of the broadcast waves reflected from the offset parabolic face. The offset parabolic face is pointed in the direction of the communication satellite such that the plane of symmetry of the offset parabolic face is coincident with a plane specified by the communication satellite, the broadcast satellite, and the receiving point of the antenna.

Abstract: Dielectric body 20 has a back surface 18, a surface of revolution about an axis 9-9. Back surface 18 has the form of a primary reflector of an antenna for transmitting or receiving microwave or millimeter wave electromagnetic radiation. A layer 15 of electrically conductive material is in contact with back surface 18. Dielectric body 20 also has a dome 23, a coaxial surface of revolution. A layer 25 of electrically conductive material is in contact with dome 23. A horn 40 fits on a protrusion 17 of dielectric body 20. Protrusion 17 aligns horn 40 on axis 9-9. The axial dimension of dielectric body 20 maintains the proper spacing between horn 40, conductive layer 25, and conductive layer 15 to enable the assembly to function as an antenna system. In the configuration shown, conductive layer 15, in contact with surface 18, forms a paraboloidal primary reflector. Conductive layer 25 , in contact with dome 23, forms the concave ellipsoidal secondary reflector of a Gregorian antenna system.

Abstract: A metallized mesh fabric construction for use as the individual reflector panels of a radio frequency (RF) deployable parabolic reflector of the type which includes a plurality of panel supporting rib members which, upon deployment, unfurl in a spiral manner from a central hub to form the parabolic reflector surface. The mesh fabric includes silver coated nylon strands and stretch resistant plastic or synthetic strands interwoven in a "Marquisette" or "Leno" style weave. The stretch resistant strands of the mesh fabric are oriented along the chordal direction (i.e., transverse to the radial direction of the unfurlable ribs) in order to withstand the tension placed on the mesh fabric during deployment of the reflector and hence maintain the shape and accuracy of the reflector surface and resist creep. The weave has openings sized sufficiently large to minimize the effects of wind load yet sufficiently small to provide good reflective performance of radio frequencies up to and including X-Band frequencies.

Abstract: A conical horn microwave antenna has a reflector positioned at the large end of a conical feed horn which has the side walls of the horn wider than the projected effective area of the reflector such that microwave absorber material lining the feed horn does not obstruct wave propagation between the feed horn and the effective reflector area.

Abstract: A mode converter for converting transverse electric modes into hybrid modes of type EH.sub.mn and including a circular waveguide provided with corrugations extending in a circumferential (azimuth) direction that become deeper toward its end and are continued in a subsequent helically outlined aperture antenna with constant depth. The emitted radiation is circularly polarized and, by the use of suitable reflectors for the emitted radiation, may be cause to be linearly polarized. The emitted radiation no longer has any sidelobes in the far field and its characteristic has a Gaussian profile over the azimuth angle.

Abstract: A shaped beam antenna system which provides a desired shape of beam, comprises a reflector and at least one primary radiator located essentially at focus of said reflector. Reflection surface of the reflector is a dense set of parabolas in which vertexes of said parabola shift on a predetermined locus which is preferably a three dimensional space curve, but not a plane curve. A second feature of the shaped beam antenna system is the primary radiator which is composed of a plurality of primary radiators positioned closely to each other.

Abstract: A multiple beam antenna system may be constructed for reducing a spillover loss n efficiency, improving beam crossover, and reducing undesired sidelobes by the addition of three dielectric lenses between a feed horn cluster connected to a beam forming network and an objective collimator. The system includes a beam forming network including a plurality of feed horns in a feed horn cluster, an objective, and an imaging lens having a lateral magnification less than unity for focusing a reduced image of the feed horn cluster at a predetermined point in space. A field lens is positioned at that predetermined point in space, and an amplitude shaping lens is positioned between the field lens and the objective. The amplitude shaping lens redirects the rays of the image transmitted by the field lens to be denser in the central region of the objective, and reduce the sidelobes of the far field pattern of the transmitted beams.

Abstract: A radar type center fed antenna comprising a small radiating horn supported at the focal point of a parabolic reflector by three struts which are oriented to minimize the parallel polarization scattering and which have a low scattering ogive cross-section. The horn is mounted at the vertex of the parabolic surface and the intersection of the three struts using a bracket that provides minimal blockage. The struts are attached to the perimeter of the reflector. One strut having a feed waveguide is attached to the top-center of the reflector and the other two are attached at points on either side of the bottom-center at thirty degree angles to the vertical plane. The strut shape and feed-horn supporting and attaching arrangement and the integration of the feed waveguide into one of the struts results in a very low sidelobe antenna that produces a far-field pattern that has very low forward scattering due to feed and strut blockage.

Abstract: A novel combined feedhorn-supporting spar and feed waveguide of ogival configuration.

Abstract: A multiple band antenna feed used with parabolic reflector antennas and the like. The feed is arranged as two coaxially disposed waveguides. A planar array of patch elements is disposed at the end of the coaxial waveguides so the energy in each band radiates from a common phase center. This simplifies the arrangement of associated subreflectors.

Abstract: A dual frequency feed for use with an antenna permits reception of signals in both a low frequency band and a high frequency band and is comprised of a single feed through which both signals are propagated, a high frequency probe which extends concentrically within the throat of the feed for receiving the high frequency signal, a wave guide connected to the throat of the feed including a pair of turnstile junctions with four wave guides interconnecting the turnstile junctions, and a single output port with a polarization rotation device for receiving the low frequency signal. The four interconnecting wave guides may be either co-axial cables or generally rectangular wave guides.

Abstract: An offset antenna having a reflector of a paraboloid of revolution and a side plate surrounding the periphery of the reflector, wherein a primary radiator is disposed within the cylindrical side plate.

Abstract: A millimeter wave Cassegrain antenna for a seeker missile wherein a sub-reflector has two side portions which can be masked in order to widen the antenna's azimuth beam width without widening the elevation pattern. The side portions of the sub-reflector are masked by a radar absorbing material which is disposed in a masking position as the missile approaches its target.