Abstract: An apparatus comprises a distributed array of antenna elements for receiving a radio frequency signal on a satellite communications link, wherein the radio frequency signal includes a known preamble; a plurality of mixers for translating the radio frequency signal to a plurality of baseband signals having in-phase and quadrature components; a processor for applying weights to the baseband signals, wherein the weights are found adaptively in response to the preamble in combination with decision-directed feedback when the preamble is not present; and a receiver for processing the weighted baseband signals. A pre-processor can be used to create sub-arrays of the antenna elements using maximal-ratio weighting. A method performed by the apparatus is also provided.

Abstract: A method and apparatus for utilizing a switched beam directional antenna in a wireless transmit/receive unit (WTRU) is disclosed. A wireless communication system includes a serving cell, a neighbor cell and a WTRU. The WTRU is configured to generate and steer a directional beam in a plurality of directions. Once the WTRU registers with the wireless communication system, the WTRU receives messages transmitted by the serving cell. The WTRU measures signal quality of messages received in each of a plurality of predetermined directions while steering the directional beam antenna. The WTRU selects a particular one of the directions having the best signal quality. As the WTRU constantly moves, the WTRU monitors signal quality in the selected direction, and switches to another direction when the signal quality in a current direction drops below a predetermined threshold.

Abstract: A phased array antenna system including a mandrel having compliant portions and an internally formed cooling passageway. The compliant portions are formed by removing portions of material along one end of the mandrel to form a plurality of pairs of generally U-shaped, leaf spring-like connecting areas. The connecting areas allow a degree of movement of a lower portion of the mandrel relative to the remainder of the mandrel, when the mandrel is fixedly secured to a printed wiring board (PWB). This enables flexible electrical interconnects, positioned over the compliant portions, to make electrical contact with circuit traces on the PWB, even if the PWB has a curved or undulating surface.

Abstract: The invention concerns a base station (100) comprising a transmission antenna (1) consisting of several radiating elements (2) for transmitting one or more radio signals (E1, E2, , EN) to one or more addressee terminals (200). Said radio signals are generated from signal components (S1, S2, , SM) to which are applied phase shifts (D1, D2, , DN). The adjustment of said phase shifts brings about a systematic fluctuation of at least one transmitting direction of the antenna during the transmission of the radio signal, so as to provide diversity of propagation paths.

Abstract: A method and apparatus for transmit power control (TPC) while switching a beam among a plurality of beams in a wireless communication system. An antenna array generates a plurality of directional beams and preferably an omni-directional pattern and switches a beam among the plurality of beams preferably including the omni-directional pattern. Link quality on at least one of the plurality of beams is measured, and a beam having a greatest link quality is selected. If the selected beam is different from a current beam, a beam is switched from the current beam to the selected beam. While switching a beam, TPC parameters are adjusted based on the link quality difference between the link quality of the current beam and the link quality of the selected beam, and optionally, base on other parameters.

Abstract: Measurements for handoff are made by a wireless transmit/receive unit (WTRU) operating with a switched beam antenna in a wireless communication system. The switched beam antenna is a smart antenna generating a plurality of directional beams and an omni-directional beam. The WTRU measures signals from a plurality of cells with the omni-directional beam and/or one or more of the directional beams. The WTRU evaluates and reports to the network measurement of the omni-directional beam or the strongest beam for adding cells to an active set of cells. For removing cells from an active set of cells, the WTRU evaluates and reports to the network measurements of the antenna beam selected for communication with the active set cells.

Abstract: A switch circuit for switching the connection of the receiving or transmitting circuits of two communication systems to an antenna circuit, which comprises first and second switch means having two switching elements, the first switch means comprising a first inductance element between a port connected to the antenna circuit and a port connected to the second switch means; the second switch means comprising a second inductance element between a port connected to the first switch means and a port connected to a receiving circuit of a first communication system, and a transmission line constituting the first inductance element having a lower characteristic impedance than that of a transmission line constituting the second inductance element.

Abstract: A method for connecting the radio link between a mobile station and a base station is provided to improve quality of received signals at the base station and the mobile station. A radio network controller (RNC) monitors the difference between the reception power of signals from the source base station BS1 and the destination base station BS2. If the base station BS2 is incapable of directional beam signal transmission and reception, and when the reception power difference becomes smaller than a first handover threshold, the radio network controller adds the base station BS2 as a radio link connection destination of the mobile station. If the base station BS2 is capable of directional beam signal transmission and reception, and when the reception power difference becomes smaller than a second handover threshold, which is larger than the first handover threshold, the radio network controller adds the base station BS2 as a radio link connection destination of the mobile station.

Abstract: A radio antenna of a radio base station is a directional antenna. The antenna searches for a peripheral radio base station by changing the directivity of the antenna. An operating channel and electric field intensity of the other base station are acquired by the searching and then stored as positional information. The operating channel of the base station, the directivity of the antenna, and a radio wave intensity communication area are set according to the acquired positional information. Further, the positional information is transmitted and received to and from the other base station to set the base station. When the base station was moved or when external noise occurred abruptly, channel change and change of a cell shape of the directional antenna are carried out. Consequently, interference between the base stations can be minimized and optimum setting of the channel and communicatable area can be realized.

Abstract: A local multipoint distribution service system having an antenna (1) for transmitting a signal of reused frequency within a specified range from the antenna (1), the antenna (1) having multiple radiating antenna elements, each of the antenna elements being adjusted in phase and in amplitude of radiated signal across the radiationg elements to mitigate radiation above the horizon, and each of the antenna elements being adjusted in phase and in amplitude of radiated signal therefrom to decrease attenuation in radiated power with distance from the antenna (1).

Abstract: A configurable directional antenna includes a center antenna element, a plurality of second antenna elements, and a switch matrix. Each second antenna element, together with the center antenna element, defines an antenna sector. A first portion of the second antenna elements is disposed at an inner radius around the center antenna element. A second portion of the second antenna elements is disposed at an outer radius around the first portion antenna elements. Each antenna sector comprises one of the radially inner antenna elements, one of the radially outer antenna elements, and a conductor extending between the one radially inner and the one radially outer antenna element. The switch matrix comprises first electronic switches for selectively grounding selected ones of the second antenna elements, and second electronic switches each for selectively connecting together the second antenna elements of one of the antenna sectors with the associated conductor.

Abstract: A satellite broadcast system and method, particularly useful for television signals, allows for local as well as nationwide broadcast service by allocating greater satellite resources to the more important local service areas. This is accomplished by broadcasting a non-uniform pattern of local service beams and designing the system to establish different service area priorities through factors such as the individual beam powers, sizes, roll-off characteristics and peak-to-edge power differentials. Frequency reuse is enhanced by permitting a certain degree of cross-beam interference, with lower levels of interference established for the more important service areas.

Abstract: In summary the present invention discloses a horn reflect array antenna system and a method for producing a signal using a horn reflect array antenna. The system comprises at least one reflective element illuminated by an incident radio frequency (RF) signal from a feed horn, the reflective element reflecting a portion of the incident RF signal as a portion of a reflected RF signal, and at least one phase shifting device, each phase shifting device coupled to a corresponding reflective element, wherein a beam pattern of the reflected RF signal is altered when the phase shifting element changes the phase of the portion of the reflected RF signal.

Abstract: Antennas with steerable antenna patterns and techniques for using such antennas are described. In accordance with the invention, antenna patterns with one or more NULLs are used. Through the use of digital control signals the antenna pattern is steered so that a source of signal interference, e.g., a multipath signal, will be located in a NULL. In this manner the received signal's S/N ratio can be maximized thereby facilitating demodulation. The techniques of the invention can be applied to television, computer devices, mobile devices and a wide range of other systems. Digital commands to control an antenna may include multiple information fields, e.g., a direction field, a channel field, a gain field and a polarity field. Antennas incapable of supporting the specified fields disregard information in fields which are not supported. Information in each supported field is decoded and used to adjust the corresponding antenna characteristic.

Abstract: The present invention provides a low-cost, steerable antenna formed with a dielectric medium separating a pair of conductive plates and a centrally located signal feed. Switches selectively interconnect the conductive plates through the dielectric medium in patterns, which determine the direction of operation of the antenna. The directionality of the antenna may be fixed or rapidly changed, depending upon the application.

Abstract: A semiconductor module having a built-in antenna element for use in a system of a band of millimeter-waves or quasi-millimeter-waves comprises a substrate, an antenna element, a semiconductor integrated circuit, and a hermetically sealing portion. The antenna element is mounted on one side of the substrate. The semiconductor integrated circuit is also formed on the same side of the substrate as of the antenna element. The semiconductor integrated circuit includes at least either of a transmitter signal processing circuit composed mainly of an amplifier circuit and a frequency converter circuit for processing a signal which is exploited in the system of the band of millimeter-waves or quasi-millimeter-waves and transmitted to the antenna element, and a receiver signal processing circuit composed mainly of an amplifier circuit and a frequency converter circuit for processing a signal which is received by the antenna element and exploited in the system of the band of millimeter-waves or quasi-millimeter-waves.

Abstract: A broadband microwave coplanar antenna suitable for use in singular antenna or antenna array dispositions in a plurality of military and other present day uses. The disclosed antenna combines desirable characteristic of the patch and slot antenna forms into an arrangement having both patch resonances and slot resonances. These resonances may be individually accessed and either combined in frequency location or dispersed in frequency to accomplish a broadband combination antenna characteristic. Broadband electrical impedance characteristics are also provided in the dispersed resonance arrangement. The antenna includes a coplanar ground plane member disposed surrounding the active patch/slot element with both physical dimensions of the active patch/slot element and spacings from the ground plane element determining the resonances.

Abstract: An antenna design includes a plurality of radiating elements which radiate electro-magnetic energy, and feeders which feed the electromagnetic energy to the radiating elements. The feeders have a supply network substantially at the same level in the antenna thickness direction. In order to achieve a small antenna with adequate properties for radio link usage, the radiating elements are arranged next to the supply network in the thickness direction and include box horn antennas which have a step, characteristic of a box horn, in the plane of the magnetic field.

Abstract: A dipole antenna is inserted into a waveguide to couple EM energy into and out of a waveguide. The dipole antenna is printed on a substrate of a module that contains electronic components. The substrate includes a coupled coplanar strip transmission line connecting the dipole antenna to a slotline. EM energy is electromagnetically coupled between the slotline and a microstrip transmission line. The EM energy is provided to and from the hermetically sealed electronic components by the microstrip transmission line.

Abstract: An active array antenna, which may be used for radar, includes antenna elements (antelements) supported in a two-dimensional array. The fronts of the elements are protected by a cover. In order to allow easy repair, each column of antelements is associated with a slide-in carrier which simultaneously mates with all antelements of a column. Each carrier has a transmit-receive (TR) module for each antelement with which it mates, and a column beamformer. Each carrier also has logic modules and power supplies for the TR modules. The total width of each slide-in carrier with its TR modules, beamformer, logic and power supplies, is less than or equal to the column-to-column spacing. Each carrier can be slid out from the rear to expose all the active components for each column of antelements, so maintenance can be performed without environmental exposure.

Abstract: An antenna having antenna modules for an extremely wideband active monopulse phased array system, the modules including a housing provided with four radiators of the rectangular open-ended waveguide type and with an electric circuit. With the antenna modules being suitably stacked, the radiators constitute a substantially continuous antenna surface, the radiators being positioned at the points of intersection of a system of equilateral triangles which make up the antenna surface. After preamplification, phase shift and down-conversion to an intermediate frequency, received signals from a large number of antenna modules are combined to yield a sum beam, an azimuth difference beam and an elevation difference beam.

Abstract: Linear array antenna systems are used in X-scan aircraft location systems and methods able to avoid disabling azimuth error conditions caused by multipath reflections under roll and pitch conditions during aircraft carrier landing operations. Aircraft azimuth and elevation data is derived based upon time of incidence at an aircraft location of two transverse, diagonally oriented, scanned antenna beams. The aircraft location data is derived by comparing time of incidence data with data on known timing of scanning of the beams, which have diagonally-oriented fan beam patterns. A plurality of vertically oriented radiating elements are typically positioned along a line diagonal to the vertical to produce a diagonally oriented fan beam pattern. Beam scanning results from relative adjustment of signal portions supplied to the radiating elements.

Abstract: A phased array antenna structure has a distribution network, and a composite of feed, module, and antenna honeycomb structures. The distribution network distributes or collects electromagnetic (EM) energy. The feed honeycomb structure is positioned adjacent the distribution network and connected to receive the EM energy from the distribution network or to distribute EM energy to the distribution network. The module honeycomb structure is positioned adjacent the feed honeycomb structure so as to receive EM energy from the feed honeycomb structure or to transmit EM energy to the feed honeycomb structure. The antenna honeycomb structure is positioned adjacent the module honeycomb structure on a side opposite the feed honeycomb structure so as to receive EM energy from the module honeycomb structure or to transmit EM energy to the module honeycomb structure. Each of the feed, module and antenna honeycomb structures have a plurality of aligned waveguides for transmitting EM energy therealong.

Abstract: An improved microwave radar antenna including a plurality of linear waveguides arranged in a two dimensional array with each linear waveguide having a mounting flange along the bottom narrow edge of the waveguide for attachment to the ground plane of the antenna by the conductive epoxy. Also disclosed is a method of manufacturing an improved microwave antenna where flanged linear waveguides are milled to provide for radiator slots and then are affixed to a attentive ground plane along the flanged edge of the waveguide by a conductive epoxy.

Abstract: An electronically tunable phased array antenna element compensates for the variation of input impedance as the scan angle of the array changes. A microstrip feed is used which allows monolithic microwave integrated circuits to easily be incorporated in the radiating element housing. The element improves transmit or receive sensitivity. In addition, this electronic tuning will counteract detuning of the element caused by external influences such as electromagnetic field coupling from other nearby antennas.

Abstract: A microwave circuit module, more particularly an antenna, comprised of a polyethylene foam substrate having a loss tangent less 0.001 and a dielectric constant less than 1.3, a predetermined pattern of one or more elements, such as an array of n.times.m radiator elements, formed of electrically conductive material, deposited on a first surface of the substrate, and an electrically conductive ground plane secured to the opposite surface of the substrate. In the antenna embodiment, a feed network formed of electrically conductive material is deposited on said said first surface of the substrate for electrically interconnecting the radiator elements in the array; and I/O means are coupled to the feed network for supplying a signal to be transmitted by the antenna or for receiving a signal received by that antenna.

Abstract: A circular waveguide section which is suitably excited with a TM.sub.01 and two spatially orthogonal TE.sub.11 modes to form a cosine-squared-on-a pedestal amplitude distribution at the outputs of the circular waveguide. The resulting cosine-squared-on-a-pedestal amplitude taper may be distributed to the elements of a circular phased array to form a low sidelobe antenna. Since the waveguide is a reciprocal element, it can be used in a receiver as well as a transmitter.

Abstract: A scanning antenna comprises a non-magnetic, electrically conductive radiation horn defining an antenna opening having a predetermined central line of focus, and at least one magnetically switchable conductive element such as a reed relay mounted to extend across the antenna opening perpendicular to and spaced from the central line of focus. A magnetic field generator such as an electromagnet is positioned to generate a magnetic field to control switching of the conductive element between its conductive and non-conductive states, and a control circuit controls operation of the magnetic field generator.

Abstract: An electronically scanned radar system has a serpentine antenna, with at least two ports. The antenna is physically rotated. Each port has a mixer, transmitter and local oscillator feeding signals to it, the signals of the transmitter and oscillator being synchronized with one another to take advantage of the physical rotation of the antenna. The radar system can be operated in various ways to produce two independent beams simultaneously in a surveillance mode and/or tracking mode at each port. Furthermore, with the use of coupling means, the system can be operated to produce four independent beams at two different frequencies simultaneously. The system can also be operated to produce one or more beams in a surveillance mode and/or one or more beams in a tracking mode at each port. Further, the system can be operated to compensate for the physical rotation of the antenna and can avoid jammers by hopping to another frequency.

Abstract: An arrangement for testing the performance of an electronic system utilizing a phased array antenna as its principal radiator into a predetermined sector of space includes, as one of its main components, an enclosure which bounds a miniature anechoic chamber located in the near-field region of the antenna array during the performance of a testing operation and lined with material that absorbs free space electromagnetic radiation. The enclosure has an opening that is aligned with the phased array antenna the performance of which is being tested. Two dual-polarized testing horn antennas are situated at a wall of the enclosure that is opposite to the wall provided with the opening. Electrical signals received from the horn antennas and representative of the near-field electromagnetic radiation emitted by the phased array antenna are supplied to an evaluating circuit which gives indication of the performance of the electronic system of the phased array antenna.

Abstract: The invention relates to a matching network which may be serially inserted in the path between a transmitter power amplifier and/or a receiver low noise amplifier and an element of a steerable array antenna to compensate for mismatching occurring when the antenna is steered away from bore sight or tuned to off resonant frequencies. The invention permits computer controlled digital setting of the matching network in accordance with the known impedance characteristics of the antenna element, to restore VSWRs which in an exemplary case may have a maximum design value of 3.0 when uncompensated to a VSWR of 1.6 with a simple matching network, or to a VSWR of 1.22 with a more highly corrected matching network.

Abstract: An array antenna is provided wherein each adjacent pair of a plurality of antenna elements in such array antenna have a common, conductive wall having a castellated radiating edge. Radio frequency energy resistive material is disposed within slots formed in the radiating edge. With such arrangement, electrical coupling between the adjacent pair of antenna elements is reduced thereby improving the gain of the antenna at the lower frequency operating band of the antenna. Further, the electric field distribution is redistributed by the slotted radiating edge from a cosine distribution associated with a linear edge to a more flattened, uniform distribution to increase the effective aperture of the element in the H-plane.

Abstract: A phased array antenna (10) includes a plurality of radiating elements (14) arranged in concentric rings (11, 12) to form a deterministically thinned antenna aperture which facilitates heat removal from the array, while minimizing side lobe signals and thereby increasing directively of the antenna for a preselected antenna gain. The radiating elements (14) in any one of the rings (11, 12) are the same radiating size, and the spacing (L, L') between elements in the same ring and between elements in adjacent rings (S, S') is determined by the number of elements in each ring. The rings may be any of several shapes, including circular or polygonal.

Abstract: A waveguide element for an electrically controlled radar antenna comprises a non-resonant waveguide (V) fed from a feed opening (M). The feed opening divides the waveguide longitudinally into a first and a second part, each provided at its outer end with absorbent terminations (A1, A2). Slits (S.sub.11, S.sub.12, S.sub.21, S.sub.22, etc) are formed in the waveguide, and their central points in the longitudinal direction have in the first part a mutual spacing (d.sub.1) which is less than half the wavelength (.lambda.g/2), while their central points in the longitudinal direction in the second half have a mutual spacing (d.sub.2) which is greater than half the wavelength.

Abstract: A steerable multibeam five element cross-feed cluster antenna (16) system. The feed power is divided into five branches. Each branch includes a switching network (12A-12E) comprised of a plurality of time delay elements (90A; 92A) each individually controlled by a respective electromagnetic latching switch (56A,B; 58A,B; 60A,B; 62A,B; 46A,B). Frequency independent individual two-dimensional beam steering at IF scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident transmit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies.

Abstract: The present invention relates to a high-power solid state amplifier arrangement comprising a large number of solid state amplifiers disposed in a waveguide array. The waveguide array is disposed in the aperture of an antenna feed arrangement at the image plane of an antenna feed to receive a uniform distribution over the array with substantially no spillover. Each of the large number of parallel waveguide sections of the array includes one or more solid state amplifiers in a serial, waveguide-interconnected, arrangement, and a wideband impedance matching arrangement in the waveguide configuration at the input and output of the section.

Abstract: An electronically scanned array antenna useful for millimeter wavelength energy is disclosed. The antenna comprises a fully ferrite loaded square or round waveguide having radiating apertures spaced along part of its length. Rf energy is circularly polarized in the waveguide. The phase velocity of the wave is controlled by applying a longitudinal magnetic field to the ferrite to produce a controllable linear progressive phase of the energy radiated from the apertures to form a beam in the desired direction. The phase control is of a latching type using flux drive. The particular structure of the invention enables combining a plurality of branching array elements with a feed element to form an array capable of two dimension beam scanning.

Abstract: A beamforming system for a linear phased array antenna system which can be sed in a monopulse transceiver, comprising a pair of series connected parallel plate constrained unfocused lenses which provide a suitable amplitude taper for the linear array to yield a low sidelobe radiation pattern. Digital phase shifters are used for beam steering purposes and the unfocused lenses decorrelate the quantization errors caused by the use of such phase shifters.

Abstract: A two-band multimode microwave source for an antenna of a low-elevation-tracking radar comprises a higher-frequency section nested in a lower-frequency section, the two sections having E-planes perpendicular to each other. The lower-frequency section includes two outer pairs of waveguides separated by a block which convergingly projects beyond their output ends and is bisected by the E-plane of that section. The higher-frequency section includes two inner pairs of waveguides disposed within that block and separated by an obstruction lying in the last-mentioned E-plane. The higher-frequency wave emitted by the inner waveguides is made planar by a lens disposed at n output aperture of the structure which is transparent to the lower-frequency wave.

Abstract: A four element antenna turnstile tracking system which outputs an azimuth error signal, an elevation error signal and an independent sum signal. Three tracking antennas are disposed triangularly at the vertices of a triangle and the sum antenna is disposed in a predetermined relationship to the tracking antennas. The three tracking antennas are symmetrically connected to a unique four port turnstile type junction which generates an elliptical wave in accordance with the difference in signals from the three tracking antennas. An orthogonal mode transducer outputs the orthogonal components of this elliptical wave, these components being the azimuth error and the elevation error signals.

Abstract: A scanning radar system having the capability of taking a number of succeve looks at the same range and angle resolution cells with several millisecond time intervals between looks. The scanning radar system includes a pulsed transmitter, a receiver, and an array of energy beam radiators having individual beam paths with associated centerlines. A commutator switch and a duplexer sequentially connect a different one of the radiators to the pulsed transmitter at the beginning of each pulse repetition period and to the receiver during the subsequent interval between pulsed transmissions. A motor rotates the array of radiators as a unit to cause the beam path centerlines to rotate and scan the field of view.

Abstract: An antenna system for locating a microwave signal source utilizing two directional finding antennas (1,2) which have major radiation lobes (3,4) which are identical and are angularly offset relative to each other in the bearing plane but overlap so that the angular position of the signal source can be identified within the overlapping range of the lobes of the two antenna by using signal level comparison or ratio formation of two signal voltages received from the two antennas (1,2). False or ambiguous bearings occurring from side lobes which overlap are avoided by the use of a pair of auxiliary radiators (13, 14) which are associated with each of the primary directional finding antennas (1,2) and wherein the primary radiation direction of the auxiliary radiators are offset in the bearing plane by a specific angle relative to the direction of the primary direction finding antennas.

Abstract: An antenna feed for decreasing the scan modulation of the radiated signal a radar which tracks by the method known as scan-with-compensation. The antenna feed is comprised of a coaxial line fed dipole located on the axis of a circular waveguide for radiating a single on-axis unmodulated pencil-beam during transmission. The antenna feed further comprises two parallel radiators located equally distant and on opposite sides of the transmitting circular waveguide radiator and functions during reception only. Rectangular waveguides connect the two parallel radiators with the central radiator so as to give rise to orthogonal signals in the central radiator upon reception of echo signals. An ATR tube connects the dipole to the central axial waveguide during transmission and isolates it during reception. The radiating dipole is mounted so as to remain fixed while the central circular waveguide and the two parallel reception waveguides rotate during scanning.

Abstract: A sum channel waveguide is excited in a TE.sub.11 mode to cause a radio frequency wave to propagate therefrom through a cylindrical multimode waveguide. The wave propagates via a discontinuity that causes the multimode waveguide to be excited in the TE.sub.11 mode and higher order modes. The multimode waveguide is coupled to free space via a dielectric lens and a cup shaped matching section, whereby the wave causes a beam to be radiated from the lens. The cavity of the multimode waveguide is contiguous with a plurality of arcuate cavities of a difference channel waveguide. The beam is deflected in response to excitation of the arcuate cavities.

Abstract: Disclosed is a coaxial waveguide antenna. In a basic form the coaxial waveguide horn for the antenna comprises an inner section operating in a .SIGMA. (sum) mode only and an outer section operating in a .DELTA. (difference) mode only. Where required for broadband (i.e., for more than 1 octave), intermediate sections operating in .SIGMA. and .DELTA. modes are provided. The basic structure operates in the linear mode; for polarization diversity and circular polarization, a polarizer is placed in front of the horn, or a dielectric sheet is positioned within a coaxial waveguide section at an angle of 45.degree. as to the E field, or by feeding the coaxial waveguide with six or more number of probes.

Abstract: An improved antenna feed providing control of the plane of polarization ecially useful with "scanning with compensation" radar tracking. An input transducer is coupled to first and second output transducers whereby the output transducers transmit two pencil-beam radiation patterns which are squinted by equal but opposite angles with respect to the scan axis. During reception, however, a non-reciprocal coupling means provides for separate sensing of the return signals rceived by the first and second output means and converts the signal received by the second output means so that it is in quadrature relationship with the signal received by the first output means.

Abstract: A feed which is stationary relative to a parabolic reflector is located in close proximity to a prime focus of the reflector along its central axis. A moving element which is opaque to r.f. energy is moved along a path of revolution about the reflector axis, the path of revolution being located between the reflector and the stationary feed. The shape of the opaque element and the path of revolution are such that different portions of the aperture of the feed are masked as the element travels along the path of revolution. This imparts predictable scanning motion to the beam pattern which is coupled into the stationary feed. One highly useful embodiment of this invention is a construction in which the stationary feed is a secondary feed installed in a nutating feed antenna, and the nutating feed itself constitutes the opaque moving element.

Abstract: An integral element/phase shifter for use in a phase scanned array. A non-resonant waveguide or stripline type transmission line, series force feeds the elements of an array. In the embodiments shown, four RF diodes are arranged in connection within the slots of a symmetrical slot pattern in the outer conductive wall of the transmission line to vary the coupling therefrom through the slots to the aperture of each individual antenna element. Each diode thus controls the contribution of energy from each of the slots (at a corresponding phase) to the individual element aperture and therefore determines the net phase of the said aperture. Three species of the invention are shown, the first and second involving RF diodes in the slots of waveguide broad and narrow walls respectively, and the third having slots through the shield plane of a stripline. The invention facilitates array phase scanning without the need for separate, and relatively more expensive, discrete phase shifters for each antenna element.

Abstract: In order to compensate for the displacement of a coherent pulse airborne radar, the latter is provided with means for alternately linearly moving forward and backward the phase centre of its antenna system, at the reception, from one cycle radar to the next.The displacement of the phase centre is carried out by introducing a controllable dissymmetry in the illumination of the linear radiating aperture of the antenna system.