Abstract: A multi-reflector antenna array capable of simultaneously transmitting and receiving communication signals at Ku-band frequencies is mounted on an exterior surface of an aircraft. The antenna array provides four cassegrain reflector antennas mechanically connected together in a group capable of being simultaneously mechanically scanned. A common support structure fixes the antennas with respect to each other. A drive mechanism and directional azimuth and elevation motors control the position of the array. The aerodynamic drag of the array is minimized using four antennas rather than a single large diameter antenna. Each antenna is positioned on a common horizontal centerline. Two centrally located antennas are positioned between two smaller diameter antennas. The antennas and positioning equipment are both mounted for rotation within a radome. A corporate power combiner/divider is provided to adjust both an amplitude and a phase of each antenna signal.

Abstract: An antenna assembly for wireless communications has various components to minimize signal influence when transmitting signals to minimize undesirable loop formation phenomena caused by (positive) feedback of signals. Signal wave scattering and diffraction causing back lobe radio frequency (RF) patterns are minimized by a particular antenna assembly structure having a reflector and at least one attenuating structural member, a metallic mesh wrapping the power cable of a feeder, a non-conductive antenna support structure, or any combination thereof. The dimensions of the various components, in particular the reflector and attenuators, can be varied according to desired wireless communications environment.

Abstract: A directive antenna includes plural antenna elements in an antenna assemblage. A feed network connected to the antenna elements includes at least one switch to select a state of one of the antenna elements to be in an active state in response to a control signal. The other antenna elements are in a passive state, electrically coupled to an impedance to be in a reflective mode. The antenna elements in the passive state are electromagnetically coupled to the active antenna element, allowing the antenna assemblage to directionally transmit and receive signals. The directive antenna may further include an assisting switch associated with each antenna element to assist coupling the antenna elements, while in the passive state, to the respective impedances. The antenna assemblage may be circular for a 360° discrete scan in N directions, where N is the number of antenna elements.

Abstract: Dual polarisation antenna having low side lobes, useful in a satellite radiocommunication system.

Abstract: A communication system and method for reconfigurably transmitting and receiving signals via a multi-beam reflector antenna array are disclosed. The multi-beam antenna system comprises a plurality of rings of single beam reflectors, each reflector having its own feed, wherein the plurality of rings are substantially concentric or nested and disposed on separate planes such that the reflectors of adjacent rings are substantially interleaved. The method, in one embodiment, comprises generating beams from a first, second and third ring of single beam feeds, respectively reflecting each beam from the first, second and third ring of single beam feeds on a separate reflector to a substantially separate coverage area, wherein the first, second and third rings are substantially concentric and disposed on separate planes such that the reflectors of adjacent rings are substantially interleaved.

Abstract: An antenna system consisting of parabolic rectangular reflectors disposed contiguously in a linear array. The use of parabolic rectangular reflectors permits the reflectors to form a larger common rectangular aperture without gaps in illumination. The contiguous array of parabolic rectangular reflectors permits a lower profile which is ideal for use on an aircraft. Each parabolic rectangular reflector has its own feed system and each of the feeds are excited in phase. The combined radiation patterns of the parabolic reflectors produces a beam with a narrow width. This narrow beamwidth permits the system to communicate with one source while filtering out signals coming from other sources. In one embodiment, the antenna system may be mechanically steered in order to communicate with a transmitter and/or receiver whose relative position is continuously varying with respect to the antenna system.

Abstract: The antenna apparatus of the present invention places antenna element 302 that transmits or receives electromagnetic waves on basic plate 301, places parasitic antenna elements 303 to 306 on basic plate 301 evenly spaced concentrically centered on antenna element 302, places switch elements 307 to 310 and capacitances 311 to 314 in parallel between one end of each of antenna elements 303 to 306 and said basic plate and disconnects one of switch elements 307 to 310 and connects all the others. In this way, the present invention provides a small and high-gain antenna apparatus with directivity switching capability.

Abstract: A common aperture reflector antenna and feed are provided for use in common aperture sensor systems. The feed includes an array of individual elements. The array elements are configured to increase the overall efficiency of a reflector antenna by flattening the aperture illumination, and also by nullifying the illumination within the centrally-blocked-portion of the reflector antenna surface. More specifically, the array elements are carefully configured with respect to spacing and excitation, for example, such that the array illuminates only the non-blocked portion of the main reflector. In addition, the array pattern is optimized such that the non-blocked portion of the reflector antenna is quasi-uniformly illuminated.

Abstract: A multiband, shaped ring focus antenna architecture employs only a single or common main reflector, that is shaped such that it can be shared by each of a pair of interchangeable, diversely shaped close proximity-coupled, subreflector-feed pairs designed for operation at respectively different spectral bands. The operational band of the antenna is changed by swapping out the subreflector-feed pairs. Placement of the shaped subreflector in close proximity to the feed horn reduces the diameter of the main shaped reflector relative to a conventional ring focus structure, so as to facilitate installation within a constrained space facility, such as a shipboard-mounted satellite communication system.

Abstract: A monopulse source for a focal feed antenna including at least two waveguides machined in a metal flange supporting a microwave transmission and reception circuit of the antenna, and a dielectric substrate on the metal flange. Also included is a microwave short-circuit having an opening with a smaller dimension than a dimension of a respective waveguide. The microwave short-circuit is mounted on the dielectric substrate such that an axis of the microwave short-circuit coincides with an axis of the respective waveguide. Further, a transition positioned on the dielectric substrate and within the opening of the microwave short-circuit is configured to couple the respective waveguide.

Abstract: An apparatus for limiting shadowing of RF coverage areas around antennas and closely associated equipment housings is disclosed. The equipment housing and antenna are located in close proximately such that the RF coverage area of the antenna is partially shadowed due to signal blockage by a face of the equipment housing or other structure. The shadowed RF coverage area is eliminated or substantially reduced by placement of a reflector to reflect emitted signals from the antenna into the shadowed RF coverage area.

Abstract: A multi-focus reflector antenna for providing a plurality of antenna patterns from a single reflector structure eliminates the need for multiple reflector antennas on a single spacecraft. The multi-focus reflector antenna includes a plurality of at least partially overlapping reflecting structures on a single support structure, each reflecting structure having a focal point and a focal axis. A plurality of RF signals radiate from the focal points, at least one of which passes through at least one of the plurality of reflecting structures and is incident upon another of the plurality of reflecting structures. The plurality of reflecting structures then direct the plurality of RF signals along the plurality of focal axis and generate a plurality of antenna patterns. The multi-focus reflector has applications in communications systems and more particularly, in satellite voice and data communications, and other RF type signals.

Abstract: A device (28) is transported into space for transmitting information from space to earth. On the device (28) there is disposed a plurality of reflectors (10) to be distributed in a raster or grid configuration on a framework (11). Of these reflectors (10), certain reflectors (10), which are selected as a function of the information to be transmitted, are brought into a position in which they reflect light beams, emanating from the sun, to the earth (26). The respective information becomes visible to an observer on the earth (26) in that the selected reflectors (10) give a sequencing of light points which corresponds to the information to be transmitted. On the other hand, the reflectors (10) which are not needed to the display of the respective information are in a position, relative to the sun, which does not allow these reflectors (10) to be perceived as light points by the observer on the earth (26).

Abstract: A passive reflective antenna located near an active receiving antennas is used to change the energy at the receiving antenna. The change in energy may be such as to remove a null created by multipath or to provide directionality, or both. The receiving antennas is permanently connected to a single receiver. When the receiver's output signal degrades below an acceptable level of quality, the reflective phase of the passive antenna's load is changed to change the phase of the reflected energy and achieve a desired effect (remove a null, change directionality, etc.) at the receiving antenna. In the simplest embodiment, the termination of the passive antenna is switched from an open circuit to a short circuit, or vice versa, to invert the phase of the reflected energy. The use of reflective elements in antenna designs, usually to achieve directionality, is well known (see the common Yagi or corner reflector antenna designs, for example), but these use passive reflector elements.

Abstract: An antenna comprising a first conductive element having a first end and a second end. The antenna is also comprised of a second conductive element having a first end and a second end. The second conductive element is adjacent and essentially in parallel to the first conductive element. The antenna is also comprised of a third conductive element connected to the first conductive element and second conductive element at their first ends therewith so signals in the third conductive element can pass to the first conductive element and second conductive element.

Abstract: It is possible to realize an antenna realizing excellent matching with impedance of an RF part without including a resonant part that accumulates large reactive power in a small volume on a finite ground formed of a body of a portable radio phone by feeding a linear conductor presenting a step structure having a part parallel to the finite ground as an antenna and juxtaposing a linear conductor having a part parallel to another one or plurality of finite grounds in close vicinity to a linear conductor having a step structure on a finite ground in contact or non-contact therewith electrically. Accordingly, it is made possible to provide a small antenna or a built-in antenna applied to a small portable radio phone.

Abstract: A Gaussian-beam antenna invention comprises a transmitting circuit or a receiving circuit, a resonator consisting of a pair of reflecting mirrors, which consist of a spherical mirror and a planar mirror or two spherical mirrors, and a transmission line which transmits a high-frequency signal between the aforesaid transmitting circuit or receiving circuit and the resonator, one reflecting mirror of the resonator having an electromagnetic wave coupling region constituted as a circular partially transparent mirror surface region having its center on the optical axis.

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: An antenna mirror scanner for generating and directing an antenna scanner beam displaying constant polarization vectors. The antenna mirror scanner includes a non-rotating fixed-aperture antenna for transmitting and receiving an electromagnetic plane wave in a form of an antenna scanner beam and a planar reflector with a reflective planar surface. A rotational axis of the planar reflector is aligned orthogonally to a direction of propagation of the antenna scanner beam propagating towards or away from the reflective surface. A motor rotates the planar reflector to direct the antenna scanner beam incident on the reflective surface either into the non-rotating fixed-aperture antenna when the antenna mirror scanner is operating in a receive mode or from the non-rotating fixed-aperture antenna when the antenna mirror scanner is operating in the transmit mode.

Abstract: A dual band signal receiver is provided with relatively coaxial antenna assemblies electromagnetically coupled to respective upper and lower band rectangular waveguides and ports through suitable polarization switching assemblies. The upper band rotatable antenna assembly consists of a dipole feed having driven dipole elements, parasitic dipole elements and a corner reflector element electromagnetically coupled to the upper band rectangular waveguide by a suitable transmission line extending substantially along the longitudinal axis or centerline of the lower band cylindrical waveguide.

Abstract: An antenna system capable of receiving electromagnetic radiation having either right or left helical polarization, and either vertical or horizontal linear polarization includes an energy concentrator which concentrates energy at a focal point. A helical antenna is arranged in the proximity of the focal point. A first switch switches the helical antenna to a backfire mode of operation and a second switch switches the helical antenna to an end fire mode of operation. A control mechanism controls the switches to select the nature of the polarization.

Abstract: The present invention relates to an antenna apparatus emitting or receiving high frequency waves and comprising four parasitic vertical rod elements disposed symmetrically to a central vertical rod element and switching elements controlled by a control circuit so that the parasitic rod elements are applied successively and periodically to the ground potential by the control circuit.

Abstract: An IFF airborne antenna including a single primary radiating element 20 with a plurality of nuisance elements 30, 40, 50 associated with the primary radiating element is disclosed in conjunction with a switching device for switching respective nuisance elements so as to selectively modify the characteristics pattern of the primary radiating element in order to obtain either an omnidirectional pattern corresponding to the pattern of the IFF surveillance mode or a first directional pattern corresponding to the fore directional pattern in the IFF interrogation mode or a second directional pattern corresponding to the monitoring pattern in the IFF interrogation mode. The switching of the nuisance elements makes it possible to selectively obtain the fore directional pattern corresponding either to a first IFF standard (Western standard) on a first frequency band or to a second IFF standard (Eastern standard) on a second frequency band which is different from the first frequency band.

Abstract: There is provided a new and useful field adjustable sectoral antenna comprising a flat reflecting surface having a front surface and first and second sides; at least one radiating element mounted in front of the front surface; and a pair of side panels each having front and rear edges and inner and outer surfaces; and wherein the panels are mounted with their inner surfaces along respective ones of the first and second sides of the reflecting surface for forward and rearward sliding movement of the side panels relative to the reflecting surface.

Abstract: An antenna system includes a reflector grid which reflects signals which are within the operative frequency range of the antenna and passes received signals of higher frequency. An absorber is placed proximate to the reflector grid to absorb signals which are passed by the grid. A second reflector located proximate to the absorber reflects signals back through the absorber such that signals reflected by the antenna system are twice attenuated by the absorber.

Abstract: A dual reflector antenna system capable of passing radiation to or from a shaped coverage area by means of a single feed, a three dimensional main reflector surface and a three dimensional subreflector surface. Desired levels and/or characteristics of radiation incident upon or received from selected regions of said coverage area are defined, and actual radiation levels and/or characteristics for said regions by modifying both said reflector surfaces are optimized simultaneously. The optimization is achieved by iteratively determining levels and/or characteristics of radiation incident upon or received from each of said regions and obtaining the least favorable value of level and/or characteristic and modifying said reflector surfaces simultaneously to obtain an improved least favorable value of level and/or characteristic.

Abstract: An antenna system in which main and subreflectors are arranged in such a manner to suppress the generation of a cross-polarized component due to the antisymmetry of the reflectors. Thereby, the antenna system can provide a preferable cross-polarization characteristics even in the working frequency bands.

Abstract: A dipole feed for a paraboloidal reflector antenna uses a conical reflector to direct the radiation of the dipole towards the concave reflecting surface of the parabola. The size and apex angle of the conical reflector are optimized to yield the desired feed pattern, the optimization parameters depending on the reflector size and focal length and being obtained numerically or experimentally to maximize reflector gain.

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: An omnidirectional antenna assembly for use with a satellite and others includes a four-element whip antenna, a first and a second reflector which are positioned to face each other, and a third reflector connecting the first and second reflectors to each other. The third reflector is provided with a frustoconical configuration and is highly conductive, whereby the range of antenna gain is broadened.

Abstract: The described embodiments of the present invention provide a high-gain antenna while allowing for the inclusion of devices within the antenna array. In one embodiment of the invention an array of receiver/transmitter elements is positioned in a pan-like reflector base. The elements are positioned one-quarter of a wavelength from the surface of the base. The wavelength is the wavelength of the chosen frequency of transmission or reception of the antenna. A partially reflective plate is positioned one-half wavelength from the base and thus one quarter wavelength from the elements. Reflective disks are also positioned one-half wavelength above the base and are positioned directly above the elements. The disks create a resonant cavity around the elements for waves of the chosen frequency arriving from near normal to the plane of the base or being emanated from the elements at a normal or near-normal angle. The partially reflective plate extends this resonant area spatially from the element.

Abstract: A large scan antenna, particularly for embarked use on board a satellite and for operation in the ultrahigh frequency range, of the type formed of a feed and a main fixed secondary reflector, the antenna being readily foldable into a launching configuration with a minimum of component elements, and comprising at least one guide G each formed of a first and a second parabolic secondary reflectors (12, 13) aligned optically along the axis of the wave guide G between the feed (10) and the main reflector (15), said wave guide G being on the one hand variable in length by moving at least one (13) of said secondary reflectors with respect to the other (12) along the axis (14) of the wave guide G, and on the other hand, rotatable about the axis (11) of the feed (10).

Abstract: An ultrasonic antenna is mounted with an ultrasonic transducer on an agricultural implement and directs an ultrasonic burst directly towards the ground in front of the agricultural implement for the purpose of range finding. The transducer receives the reflected signal and, following signal processing, a computation is made of the height of the reference point on the implement above the ground. Ground tillage, seeding, and similar equipment including above ground harvesting implements can be controlled with the equipment. The antenna is characterized by a moulded body having a sensor mounting at one end and an opening at the other end with co-operating first and second concave surfaces for reflecting the ultrasonic beam between the sensor and the opening and vice versa.

Abstract: A small linearly polarized adaptive array antenna for communication systems is disclosed. The directivity and pointing of the antenna beam can be controlled electronically in both the azimuth and elevation planes. The antenna has low RF loss and operates over a relatively large communications bandwidth. It consists, essentially, of a driven .lambda./4 monopole surrounded by an array of coaxial parasitic elements, all mounted on a ground plane of finite size. The parasitic elements are connected to the ground plane via pin diodes or equivalent switching means. By applying suitable biasing voltage, the desired parasitic elements can be electrically connected to the ground plane and made highly reflective, thereby controlling the radiation pattern of the antenna.

Abstract: A reflector antenna system with reduced blockage effects is provided by placing a compensating reflector between the surface of the main curved reflector and its primary feed to intercept illuminating radiation which would otherwise be blocked by the feed. The compensating reflector reflects the intercepted radiation with a beam pattern which is essentially identical to the substractive blockage pattern. The compensating reflector is spaced from the main reflecting surface to place its beam pattern in phase opposition to the blockage pattern to cancel common components from the blockage pattern.

Abstract: A millimeter wave dual beam line scanning antenna integral with a tunable solid state oscillator is disclosed. The antenna provides two fan-shaped beams from opposite faces and when the antenna is rotated, a roughly conical shaped scan obtains. Furthermore, variation of the oscillator frequency causes a variation in radiation angle and provides two line scanning beams from opposite faces.

Abstract: The present invention relates to a multibeam antenna arrangement comprising a main focusing reflector, a doubly curved subreflector disposed confocally with the main reflector and a plurality of feeds disposed on a doubly curved focal surface of the antenna on which an image of the far field of view is formed. The subreflector is doubly curved in orthogonal directions to introduce a predetermined amount of barrel distortion for transforming a three-dimensional, non-rectangular, matrix in the far field of the antenna arrangement into a substantially rectangular matrix on the doubly curved focal surface of the antenna arrangement. Feeds are aimed such that a central ray from each feed reflected by the subreflector impinges a common point on the main reflector.

Abstract: The orientable beam antenna comprises a fixed source, a fixed first reflector and a mobile reflector. The axis of the source is offset with respect to the focal aspect of the fixed reflector, and the mobile reflector connected to the elements through a universal joint device having two orthogonal axes, enabling the mobile connections to be limited to commercially available bearings.

Abstract: A single microwave-reflective antenna "dish" can be used in combination with a plurality of multiple-beam microwave feed arrays to generate or receive multiple-beam-path microwave radiation in several different frequency bands. Each of the feed arrays may operate in a discrete band of frequencies, with the combined radiations of all the arrays illuminating the reflector along a single axis. The optical system is based on the Newtonian model, such that the radiations from several arrays located off the principal axis may be combined by corresponding frequency-sensitive reflective surfaces located on the principal axis. Each of these reflective surfaces serves to direct the radiations from a single feed array toward the reflective antenna, and reciprocally, to direct radiation from the antenna to the associated feed array.

Abstract: A subreflector and reflectors in a primary radiation system, these constituting an offset dual-reflector aerial, are subjected to the so-called reflector-surface shaping. The main reflector is formed as a part of a revolutional paraboloid, and is a combination of a number of congruent reflector-segments. With such an arrangement, the manufacturing cost of a large-sized main reflector is reduced. The production error, and the aerial gain reduction and the deterioration of a wide-angle directivity due to the production error are minimized.

Abstract: A reflector antenna system is described suitable for ground stations used in communication with geostationary satellites. Dual beams or multi-beams can be directed at several satellites spaced angularly from 5.degree. to 20.degree. apart and these beams are scanned by feed motion keeping a single main reflector surface fixed. Offset feed geometry is used for low aperture blocking and shaping of subreflectors and main reflector results in very high aperture efficiencies, low sidelobes and symmetric low cross-polarization patterns needed for satellite links. A novel method for shaping subreflectors using the ratios of ray lengths squared and variable focal lengths is applied in the optimally tilted offset geometry results in almost uniform aperture power distributions.

Abstract: A five-horn Cassegrain antenna is disclosed comprising a main dish, an up-taper subreflector set on the boresight axis of the main dish, and including a sum horn positioned on the boresight axis between the subreflector and the main dish with four error horns set therearound. The aperture of the sum horn is relatively large to substantially eliminate radiation spillover at the up-taper subreflector. The error horns are positioned around this large aperture sum horn such that the radiation patterns of paired error horns will crossover in their sidelobes. These error horns are provided with a high aspect ratio with the narrow dimension of each error horn being located in the plane of its tracking crossover with the radiation pattern of the other error horn with which it is paired.

Abstract: A conical scan microwave antenna having a stationary fixed axially symmetric primary reflector consisting of any concave surface of revolution along with a spherical wave point source feed-and-subreflector assembly potentially rotatable about the axis of the primary reflector, and with the surface of the subreflecror being shaped so that the reflection of the spherical wave from the feed and off of the subreflector strikes the primary antenna and is reflected as a co-planar wavefront from every point on the primary reflector, and, further, the subreflector-and-feed assembly is located outside of the aperture of the reflected pencil beam such that for any given scan position of the subreflector, no portion of the reflected wavefront intersects the subreflector or its feed.

Abstract: The present invention relates to an antenna arrangement capable of generating one or more linearly scanning spot beams which are scanned over separate strip portions of the entire field of view of the antenna. The antenna arrangement comprises an optical system comprising an aperture and a focal plane, and a novel feed arrangement. The feed arrangement comprises a separate linear phased array disposed within a separate rectangular waveguide section for each linear scanning beam desired. An offset curved reflector, disposed in each waveguide section, converts a linearly scanning planar wavefront generated by an array into a converging beam forming a linearly moving point source on the antenna's focal plane with the principle ray of each instantaneous wavefront being directed at the center of an image of the aperture of the optical system as seen by the feed arrangement.

Abstract: An antenna structure includes an at least partly parabolic main reflector and an auxiliary reflector of generally similar configuration, the two reflectors having confronting concave surfaces and lying respectively above and below a horizontal plane including a common focus of these surfaces. A corrugated horn illuminating the auxiliary reflector extends at the level of the latter, with a substantially horizontal axis, between vertical planes passing through the vertex of the parabolic main-reflector surface and through the common focus; in one embodiment, the horn forms with the auxiliary reflector a unitary assembly closed on all sides except for an upper aperture facing the main reflector.

Abstract: The present invention relates to antennas which have reflector arrangements that produce a large image with minimal aberrations at the exit aperture thereof of a small feed array. In the present arrangement, the feed array is placed at the conjugate plane relative to the exit aperture of a geometrically confocal reflector system comprising a parabolic main reflector and a parabolic subreflector so that exact imaging of the array is obtained at the exit aperture. In such arrangements, alignment and surface accuracy errors of the various reflectors can be easily corrected by appropriately changing the phase or the position of the associated elements of the feed array. A three-reflector arrangement having sequential geometric confocality is disclosed which also alters the focal length of the main reflector sufficiently to permit the inclusion of polarization and/or frequency diplexing means in the overall reflector system.

Abstract: An aerial system (antenna system) comprisesdual-reflector aerial consisting of a main reflector and subreflector;a primary feed whose input and output ends are fixed for elevation and azimuth rotation of said dual-reflector aerial;a plane reflector which is turned together with said dual-reflector aerial around an elevation rotating axis;a first curved reflector for reflecting waves generated from said primary feed; andsecond and third curved reflectors which sequentially reflect to lead the wave reflected by said first curved reflector to said plane reflector.

Abstract: The present invention relates to an antenna system for providing substantially perfect axial symmetry in the radiation pattern which combines (a) a curved main reflector, (b) at least two confocal subreflectors disposed to sequentially reflect a ray in either direction between the main reflector and a focal point of the antenna system as provided by the subreflector most distant along the feed axis from the main reflector, and (c) a symmetrical feedhorn disposed at the focal point of the antenna system so that its longitudinal axis coincides with the equivalent axis of the antenna system.

Abstract: The present invention relates to novel launcher reflectors which are used with reflector antenna systems to compensate for the dominant aberration of astigmatism which was found to be introduced in the signals being radiated and/or received at the off-axis positions. A major portion of such phase error is corrected by using, with each off-axis feedhorn, an astigmatic launcher reflector having a curvature and orientation of its two orthogonal principal planes of curvature which are chosen in accordance with specific relationships, the launcher reflector being fed by a symmetrical feedhorn.

Abstract: A bifocal pillbox antenna system is disclosed comprising a controller means providing control voltages and sequential switching signals to scan circuits. The scan circuits provide RF energy selectively to feed elements of a contoured feed array for radiation in a waveguide means. The waveguide means includes a waveguide and a pair of reflectors specially shaped to provide a pair of spaced focal points. The energy radiating from the feed elements with a non-linear phase distribution is guided to the specially shaped reflectors and reflected with a nearly linear phase distribution for transmission.