Abstract: A bandpass radome that reduces the number of spurious resonances, and that tends to suppress Transverse Magnetic TM and Transverse Electric TE surface waves, is described. In one embodiment, the radome includes an inductive FSS ground plane layer. First and second capacitive FSS layers are disposed above the inductive ground plane layer. Third and fourth capacitive FSS layers are disposed below the inductive ground plane layer. In one embodiment, the capacitive FSS layers use patch elements and some or all of the FSS patch elements above and below the inductive ground plane layer are electrically connected to the inductive ground plane layer by a conducting posts. The conducting posts form a rodded medium to suppress TM and TE surface waves. In one embodiment the total thickness of the bandpass radome is less than &lgr;/20 at the center frequency of the passband.

Abstract: A hood is provided for verifying the performance of the missile. The hood includes one or more sense antennas having the same polarization as the antennas within the missile to be tested. The hood further includes one or more elliptic-to-circular polarization converters designed to reduce the axial ratio of the signal received from the missile. The elliptic-to-circular polarization converters convert the signal from the missile to a substantially pure circular polarized signal which is then sensed by the sense antennas.

Abstract: An antenna system that employs antenna elements for both transmit and receive functions. Signals received by each antenna element are directed to a dual band polarizer that converts the signals to linearly polarized signals, and signals to be transmitted by each antenna element are converted to circularly polarized signals by the polarizer. The orientation of the polarizer and whether the circularly polarized signals are LHCP or RHCP determines whether the linearly polarized signals are vertically or horizontally polarized. A dual-band orthomode transducer is employed to separate the receive and transmit signals into their respective frequency bands based on whether they are vertically or horizontally polarized. The transducer is a waveguide device having only three signal ports. A high pass filter is used to help separate the received signals, and a low pass filter is used to help separate the transmit signals.

Abstract: An ultra-wideband, multi-beam adaptive antenna includes a phased array system having an ultra-wideband antenna. The antenna further includes at least two sub-arrays of antenna elements for receiving radio frequency (RF) signals located in a respective at least two sub-bands of a desired wide frequency band. The sub-arrays are interspersed to provide a single wideband antenna, which is coupled with a phased array system having multiple beamforming networks.

Abstract: A dielectric plate, serving as a 90-degree phase device, is disposed inside a waveguide. A phase-converting portion of uniform thickness is formed at the central portion of the dielectric plate, and stepped portions, serving as impedance converting portions, are formed at both longitudinal end portions of the phase converting portion by causing protrusions to be protrude from both of the longitudinal end portions. The protrusions are disposed on orthogonal axes extending in widthwise and thickness directions of the dielectric plate. The protruding amount of each of the protrusions from end surfaces of the phase converting portion is approximately ¼ of a wavelength &lgr;g inside the waveguide. The end surfaces of the phase converting portion and corresponding end surfaces of the protrusions form reflecting surfaces that are orthogonal to the direction of propagation of an electrical wave.

Abstract: The present invention features a stacked, multi-band, antenna system consisting of a low-frequency, forward portion and a gridded, rear portion designed for operation at a higher frequency. Both front and rear radiating elements may share a common ground plane or the rear element may form a ground plane for the front element. Typically, the front antenna is a relatively narrow-band, gridded, bow-tie dipole or a similar radiating structure and the rear antenna is a wide-band dipole or slot element. Additional frequency bands may be designed into the inventive system by adding additional dipole or similar antenna elements above, below, or between the front and rear antennas. By properly choosing element sizes and spacings, and orienting the various antennas, a frequency band ratio of as little as 4:1 may be obtained.

Abstract: A low noise block down converter adapter for an antenna includes a Y-shaped housing that is mated to one end of a support bracket, as well as a plurality of low noise block down converters with feed (LNBFs). The adapter incorporates a plurality of ports for connecting to the LNBFs, a plurality of outputs to a plurality of integrated receiver-decoders (IRDs), and a multi-switch for selecting among the connectors to connect a selected one of the plurality of LNBFs to a selected one of the outputs.

Abstract: A dual-band electronic scanning antenna, with an active microwave reflector. The antenna includes at least two microwave sources transmitting in different frequency bands and having opposite circular polarizations. An active reflecting array including elementary cells illuminated by the sources is provided. A polarization rotator is inserted between the reflecting array and the sources, changing the circular polarizations into two crossed linear polarizations. An elementary cell includes a conducting plane and first and second transverse phase shifters, the first phase shifter is substantially parallel to a linear polarization and the second phase shifter is substantially parallel to the other linear polarization. The conducting plane is placed substantially parallel to the phase shifters. The antenna is applicable in particular for microwave applications requiring two transmission bands moreover subject to very low-cost production conditions.

Abstract: An improved low-angle radiation antenna is obtained through excitation of a tangential electric field on the high-impedance surface, as well as leaky transverse-electric surface waves. Such fields and surface waves cannot normally occur on an ordinary metal surface. The tangential electric field on the high-impedance region excites a transverse-magnetic surface wave on a surrounding metal surface which gives improved low-angle radiation in the E-plane of an antenna disposed on the high impedance surface. Leaky transverse-electric surface waves provide improved radiation in the H-plane of the antenna.

Abstract: An apparatus and method for microwave imaging and sounding with large bandwidth radiometer reflector antennas in a compact form. The apparatus comprises a main reflector for reflecting a beam, a polarizer for polarizing the reflected beam into a first polarized beam and a second polarized beam, a first Frequency Selective Surface (FSS) reflecting a first selected frequency of the first polarized beam, a second FSS reflecting a second selected frequency of the second polarized beam, a first feed receiving the first selected frequency and a second feed receiving the second selected frequency. The method comprises reflecting a beam, polarizing the reflected beam into a first polarized beam and a second polarized beam, reflecting a first selected frequency of the first polarized beam, reflecting a second selected frequency of the second polarized beam, receiving the first selected frequency and receiving the second selected frequency.

Abstract: The disclosure relates to a process of cyclic detection in diversity of polarization of digital cyclostationary radioelectric signals. The process consists in acquiring the signals on a network of at least two of antennas, in calculating a cyclic covariance matrix on a first moment, and on a second moment, of a spectral correlation of the digital signals acquired, and in detecting peaks of spectral correlation by comparing a likelihood ratio with a detection threshold determined statistically. The invention is applicable notably to digital radioelectric signals emitted by a satellite.

Abstract: A spaceborne hybrid antenna reflector for dual frequency band illumination of common spot beam coverage regions contains an interior solid reflector region, that is adjacent at its perimeter to a ring-shaped exterior dichroic reflector region and adjoined by a common backing structure. The solid interior region is reflective to RF energy at each of first and second spaced apart frequency bands, while the exterior dichroic reflector region is reflective at the first frequency band, but non-reflective at the second frequency band. This allows the hybrid reflector to realize the same beamwidth coverage for a transmitter operating at one frequency band and a receiver operating at the other frequency band. The backing support frame at the rear side of the reflector is electrically decoupled from the exterior dichroic ring.

Abstract: A circularly polarized single point feed notch antenna functions on land, sea, air and space vehicles and communicates using a broad frequency range while maintaining stealth during installation on a fighter aircraft by demonstrating a low Radar Cross Section (RCS). The circularly polarized notch antenna (CPNA) employs a phase delay card polarizer to achieve circularly polarized radiation or reception. The CPNA couples non-planar conductive fins to opposing sides of a non-conducting polarizing member. The fins fashion a ninety degree longitudinal fold, tuning slots at one fin end for tuning the antenna, and bifurcated arms at an opposing end formed by a notch. The bifurcated fins possess curved edges running from a part exterior to a part interior and a recession on the fold beginning near the tuning notch(es) and running the fin length until the recession runs out when it meets the curved edge.

Abstract: The invention provides an artificial magnetic conductor (AMC) system and method for manufacturing. The AMC has a post plane with posts and slots. The posts are operatively disposed adjacent to conductive shapes on one or more frequency selective surfaces. The posts formably extend from the post plane.

Abstract: A layered, electronically scanned antenna. The antenna includes a plurality or array layers separated by dielectric spacers. Each array layer includes a transistor switched grid formed by a plurality of reflective/transmissive elements such as cross dipoles interconnected by a plurality of semiconductors, such as MOSFETs. When the switched grid is in an open state, its associated array layer is reflective. When it is in a closed condition, its associated layer is in a transmissive state. By controlling the state of each array layer, a desired degree of phase shift can be imparted to the signal reflected by the antenna. The antenna thus eliminates the need for costly MEMS/MMIC technology to achieve the desired degrees of phase shift of a signal reflected by the antenna.

Abstract: A multi-layer grid (20) for an antenna system (10). The multi-layer grid 20 includes a first panel (22) and a second panel (24). Each panel is formed utilizing a pair of outer layers (26, 28) which are adhered to a dielectric foam (30). A low loss adhesive layer (32, 34) enables bonding of dielectric foam (30) to each of respective outer layers (26, 28). A spacer (38) provides a predetermined spacing between first panel (22) and second panel (24). A frequency selective surface filter (38) is disposed on the outer layer (28) of each panel (22, 24).

Abstract: The present invention provides a programmable image antenna formed on the face plate of a cathode ray tube (CRT) or on another substrate. The inner CRT face is coated with a silicon semiconductor material replacing conventional phosphors utilized in CRTs for generating visual images. An electron beam impinging upon the silicon-coated CRT face plate creates conductive areas during liberation of minority carriers, in the form of electron-hole pairs. Antenna elements having a virtually unlimited variety of shapes and/or sizes can be formed on the CRT face.

Abstract: Array fed multiple beam antenna systems and methods for use on an orbiting spacecraft carrying a communication system. The antenna systems include a reflector and a relatively small array feed compared to the reflector. The array feed has feeds (radiators) that illuminate the reflector and that are disposed in a focal plane of the reflector. A power division network excites the radiators of the feeds. The antenna system is capable of very wide scan angle operation and may be used to provide multiple spot beam coverage over the surface of the Earth viewed from a synchronous orbit spacecraft. Phase aberration normally associated with scanning is corrected by adjusting excitation coefficients of each array feed. The spot beams are scanned across a field of regard by controlling the position of each feed in the focal plane and using the appropriate amplitude and phase distribution associated with a particular spot beam (array feed). The amplitude and phase distributions may be fixed or varied during operation.

Abstract: An antenna intended for radiating and receiving electromagnetic waves and including a parabolic reflector and an exciter, which is designed as a sub-reflector and which is attached in the focal point of the reflector at the end of a waveguide, guided through the center of the reflector. On the backside of the reflector a radio box, containing electric and electronic components, is attached to the waveguide, which is connected to a transmitter-receiver. To increase the transmission capacity, a polarization diplexer is provided between the radio box and the waveguide for simultaneous transmission of two orthogonal, linearly polarized waves. The diplexer has first and second inputs with an essentially rectangular clear cross section and an output, which can be attached to the waveguide.

Abstract: An antenna includes first and second arrays spaced apart by a dielectric slab having a predetermined thickness, each of the first and second arrays provided from antenna elements having a linear polarization with the antenna elements in said first array disposed orthogonally to the antenna elements in said second array. The antenna further includes a feed circuit coupled to said first and second antenna arrays to provide said first and second antenna arrays having a phase relationship such that the antenna receives and transmits signals having circular polarization and dielectric material having differing characteristics for providing an impedance transformation that varies with scan angle in accordance with the a scan impedance of said antenna thereby providing the antenna having a scan impedance which is substantially the same over a scan sector while at the same time preserving the response characteristic of the antenna to signals having circular polarization.

Abstract: The invention concerns a frequency converter arrangement for parabolic antennae receiving vertical and horizontal linear polarization signals, transmitted by two geostationary satellites not far from each other. The arrangement comprises two positive converter devices (5, 6) designed to receive the signal derived from a satellite, each device bearing means ensuring that the receiving antennae elements are oriented in the received signal plane and means to adapt to the different elevations of the two satellites, by rotating the converter device support. The arrangement is characterized in that the output portions (10) of the two converter devices (5, 6) are made in the form of a single-piece part (12) whereas the input portions (9) are separated and mounted selectively adjustable on the single-piece part (12), the arrangement being mounted rotating about an axis parallel to the two input portions (9).

Abstract: An antenna feed system capable of simultaneously receiving and transmitting in multiple frequency bands is disclosed. In one embodiment, the feed system comprises a dielectric loading rod, an inner cylindrical waveguide, and one or more outer cylindrical waveguides. The dielectric loading rod lies along a central axis, as do the inner waveguide and outer waveguides. The axis of the inner waveguide and the rod may coincide. Each waveguide may be configured to receive and transmit a different frequency band simultaneously with the other waveguides. In addition, the axes of the outer waveguides also coincide with the central axis. The antenna feed system may further comprise one or more junctions disposed to propagate electromagnet radiation into and out of the inner waveguide and outer waveguides. A method and kit for simultaneously receiving and transmitting in multiple frequencies are also disclosed.

Abstract: The invention relates to an antenna system for motor vehicles. This system allows mobile reception of television and radio broadcasts and of data of geostationary satellites independently of the operating condition of the vehicle. The system is for an antenna arrangement for the frequency range greater than 10 Ghz with quasi-omni-radiation in the horizontal direction.

Abstract: A method and a device are disclosed for the generation of a surface, the reflection phase gradient or transmission phase gradient of which will be varied by means of a controllable static electric field. The present solution takes into account, instead of mainly the transmissive properties, also the reflection properties of an arrangement comprising a ferroelectric material. Such a reflecting surface may contribute to an entire antenna aperture, a portion of an antenna aperture or an element in a conventional array aperture. In a general case N lobes and M nulls are to be controlled at the same time. In such case the surface will preferably be designed as a curved surface, for instance a rotation symmetric parabola, while in other cases the reflector element may be designed just as a plane mirror. An antenna comprising such a reflector element of ferroelectric material can also form a polarization twisting Cassegrain antenna with a flat or curved main reflector element.

Abstract: The addition of semiconductor spacers into the spaces between the metal strips of a metal grid permits electron-hole plasmas to be introduced there controllably. Thus, the grid can be made to transmit or reflect an incident wave with a polarization perpendicular to the strips depending on whether or not the spacers are filled with minority carriers. The presence of carriers may be controlled electrically, optically and by field effect means which permit the basic metal strip/semiconductor structure (MGSS) to operate as a reconfigurable hologram, a reflector, a phase shifter, a switch, and a beam-steering antenna.

Abstract: An antenna (1) having an EM feed (6), a rear parabolic twist reflector (3) and a front transreflector (2). The transreflector is closer to the parabolic twist reflector than the focal point of the parabolic twist reflector, and the twist reflector is defined, mounted, or otherwise formed on a parabolic surface (17) of a base (13). The base is dimensioned and arranged to provide a foundation aligning an axis of the parabolic twist reflector with an axis of the antenna, and is further dimensioned and arranged to maintain substantial alignment of the feed and twist reflector with variations in ambient temperature that would otherwise produce at least one of warping and misalignment of the parabolic twist reflector in the absence of the base.

Abstract: A slip joint polarizer including a stationary waveguide rotatably connected to a moveable waveguide, e.g. an ortho mode transducer, by a mating interface, such as a pair of rotatable mating flanges. The moveable waveguide is rotatable with respect to the stationary waveguide to adjust at least one of receive and transmit polarity. A probe extends axially in the moveable waveguide, passing through the mating interface and into the stationary waveguide. The probe may be attached to the moveable waveguide so that the two rotate simultaneously. Alternatively, the probe may rotate independent of the moveable waveguide to adjust for transmit polarity. During installation, the moveable waveguide is rotated with respect to the stationary waveguide in order to adjust receive and/or transmit polarity. Once properly adjusted, the rotatable mating flanges are locked together to prevent movement.

Abstract: A frequency selective reflector is provided for use in an electromagnetic antenna system, wherein the frequency selective reflector reflects electromagnetic waves having two or more frequencies. The reflector includes an inner portion which has a reflective surface which will reflect at least first and second frequencies. The reflector also includes an outer portion which will reflect electromagnetic waves having the first frequency in substantially the same direction as electromagnetic waves of the first frequency reflected from the inner portion. On the other hand, the outer portion is constructed to prevent the constructive reflection of electromagnetic waves of the second frequency in the same direction as electromagnetic waves of the second frequency reflected from the inner portion.

Abstract: A system for wire detection comprising a transmitter for transmitting multi-polarity waves, means for receiving waves reflected off target and means for analyzing the polarization of the reflected waves to detect linearly polarized echoes characteristic of wires and to issue a warning indicative of the presence of a wire. The wavelength of the transmitted waves is larger than the diameter of the wires to be detected. A method for wire detection comprising the following steps, for each of a plurality of angles U between 0 and 180 degrees: a. Transmit pulses of electromagnetic waves having a linear polarization at an angle U to horizontal; b. Receive echoes at the same polarization angle U; c. Prepare a map M(U, R) with the magnitude of the received echo for each angle U and each ground cell at range R.

Abstract: A polarizer for a dual frequency band is formed of square waveguides of a dual structure. A section is formed which extends in a step-like manner as deeper inside between outer and inner square waveguides. The section is connected to the inner square waveguide at an output portion. A third section protrudes from the sidewall of the inner square waveguide, which section extends in a step-like manner as deeper inside and connected to the other sidewall of the square waveguide at the output portion to provide two divided rectangular waveguides.

Abstract: A multiple band, polarization diversified antenna system that accommodates a plurality of independent and separate antenna subsystems that share a common aperture and boresight. The antenna system includes a first low-band antenna subsystem for one polarization mode in a low frequency band, a second low-band antenna subsystem for another polarization mode in the low frequency band and a high-band, dual-polarization, dual-reflector antenna subsystem for two high-frequency antenna subsystems having orthogonal polarization modes. The dual-reflector antenna subsystem includes a main reflector, a sub-reflector and a support cone. The two low-band antenna subsystems and the high-band, dual-polarization feed subsystems are all positioned behind the main reflector of the high-band dual-reflector antenna subsystem. The signals transmitted by the high-band antenna are directed towards the sub-reflector and are reflected therefrom to be directed towards the main reflector.

Abstract: An antenna system comprising a first reflector and a second reflector is disclosed. The first reflector reflects an incident signal from a signal source. The incident signal comprises a first signal having a first polarization and a second signal having a second polarization. The first reflector has a surface that reflects the first signal and the second signal. The second reflector receives the reflected incident signal from the first reflector and comprises a first reflective surface for reflecting the first signal and a second reflective surface for reflecting the second signal.

Abstract: A microwave antenna (10) is formed from a stack of generally planar elements (14-122) forming an array of horns (12) communicating with waveguides (38). The generally planar elements (14-22) are of metallized plastics. Each of these elements (14-22) has a given overall thickness which is constituted by a membrane of relatively small thickness formed (typically by vacuum forming) into a corrugated shape.

Abstract: The invention relates to a device for transmitting and receiving microwaves including a planar radiating element. The device is characterized in that the radiating element (60) has substantially orthogonal transmit and receive ports (68, 66) and the relative phase of the transmit and receive signals and the shape of the radiating element are such that the transmit and receive signals, whose frequencies are different, are circularly polarized in opposite directions.

Abstract: A frequency selective surface includes at least one frequency selective layer (1) made up of an array of electrically conductive elements (2, 2a, 2b), at least one frequency selective layer (3) having an array of non-conductive apertures (4) therethrough overlaying the element layer (1) and a dielectric layer separating the two layers (1, 3). The element layer (1) is complementary in plan view to the aperture layer (3). The element layer (1) and the aperture layer (3) are rotated through 90 degrees in plan with respect to each other and substantially parallel to one another and the element array and the aperture array have the same periodicity.

Abstract: Coaxial waveguide apparatus for conducting radio signals within a range of frequencies including an waveguide having an open end and a rear wall opposite the open end positioned along an axis of the waveguide and defining a waveguide cavity with a fundamental waveguide mode within the waveguide. The waveguide is constructed with a cutoff frequency for the fundamental waveguide mode which is at least 95% of the lowest frequency for the apparatus. A center conductor is positioned within the waveguide cavity and along the axis of the waveguide so that the center conductor and the waveguide define a coaxial waveguide cavity.

Abstract: An antenna feed for a 94 GHz radar combining quasi-optic and microwave integrated circuit (MIC) techniques. The optical components (15-23) couple MIC receive and transmit boards (FIGS. 2, 3 and 4) to the antenna, which may be a steerable cassegrain. Co-polar and cross-polar received signals are coupled out of the optical system by transmitting/reflecting grids (3 and 5) and the transmit signal may be similarly coupled into it (7). The MIC's have antenna patch arrays which are oriented to suit the respective polarization plane and associated grid. The use of a Faraday rotator (17) in conjunction with a grid (5) in the optic path permits spearation of the transmit path (13) from the receive path (25), each then having it own MIC (FIG. 4 and FIG. 3). Alternatively, duplexing is performed in a common MIC (FIG. 6).

Abstract: A polarizer for two different frequency bands is described for exciting an antenna with a parabolic reflector. The polarizer has a waveguide section capable of carrying in each frequency band two mutually perpendicularly linearly polarized waves. For each frequency band, two waveguides having a rectangular cross-section are connected to the waveguide section separate from each other and mutually offset in the axial direction of the waveguide section. A respective waveguide is connected directly to the waveguide section for each polarization direction of the lower frequency band, whereas for the upper frequency band—from a connecting point (11, 12) on—each of the two waveguides is subdivided into two branches (18, 19, 20, 21) with each having identical rectangular cross-section. The respective branches terminate on the waveguide section at mutually opposing locations which are circumferentially offset relative to each other by 90° for the two polarization directions.

Abstract: A polarization compensating device useful in correcting radome-induced polarization errors in a linearly polarized antenna in a missile is described.

Abstract: Disclosed is a common aperture dual polarization antenna array (30). This common aperture dual polarization antenna array (30) includes an antenna aperture (36) and a plurality of centered slot arrays (32) positioned within the antenna aperture (36). A plurality of notch dipole arrays (34) are positioned within the antenna aperture (36) and positioned substantially orthogonal to the plurality of centered slot arrays (32). A first feed guide (46) is coupled to the plurality of centered slot arrays (32) and a second feed guide (56) is coupled to the plurality of notch dipole arrays (34).

Abstract: The invention relates to an antenna source transmitting and receiving polarized microwaves, the source including a transducer for separating the transmission signals from the reception signals, the frequencies of the transmission signals being different from the frequencies of the reception signals. The connection between the transducer and the radiating element of the antenna is such that it maintains the polarization states of the signal received by the radiating element and of the signal transmitted to said radiating element. The transducer comprises a square-section waveguide, one end of which is connected to the radiating element, the other end being connected to the transmission path, the received signals being conveyed by the side faces of the waveguide. This source makes it possible to transmit and to receive in the enlarged C band, i.e. 3.4 GHz to 4.2 GHz on reception, and 5.85 GHz to 6.65 GHz on transmission.

Abstract: A multi-mode, multi-step feed horn (10) for a satellite antenna array that includes multiple transition steps (28-34) that provide control of the mode content of the signal, and the generation of substantially equal E-plane and H-plane beamwidths, with low cross-polarization and suppressed sidelobes. In one particular embodiment, two transition steps (32, 34) allow the E-plane to expand and generate the higher order TM.sub.11, propagation mode. The transition steps (32, 34) and a phase section (18) allow the mode content to be oriented relative to each other in the proper phase so that the useful bandwidth is on the order of 10%-15%. Two other transition steps (28, 30) provide impedance matching between a throat section (12) and the mode content transition steps (32, 34) to prevent or minimize reflections.

Abstract: A waveguide antenna has two orthogonal feeds from coaxial conductors into a round or square waveguide sections. The feeds are coupled into the waveguide section by first and second coupling devices arranged orthogonally about the main axis of the antenna.

Abstract: A polarizer for two different frequency bands for exciting an antenna with a parabolic reflector has a waveguide section capable of carrying in each frequency band two mutually perpendicularly linearly polarized waves. For each frequency band, there are connected to the waveguide section, separate from each other and mutually offset in the axial direction of the waveguide section, two waveguides having a rectangular cross-section. For the lower frequency band, for each polarization direction, a respective waveguide is connected directly to the waveguide section. For the higher frequency band, starting at a connecting point, each of the two waveguides is subdivided into two waveguide branches with identical rectangular cross-sections, with the branches terminating at two opposing locations of the waveguide section. The locations, where the branches for the two different polarization directions terminate on the waveguide section, are circumferentially offset relative to each other by 90.degree..

Abstract: A Cassegrain antenna system includes a flat dielectric plate radome having a thickness of one-half wavelength at a frequency of operation. The plate has an electrically conductive grid disposed on an inside surface thereof to permit perpendicularly polarized energy rays to pass there-through. A parabolic twist reflector is spaced from the radome, and includes a dielectric substrate having a thickness equivalent to one-quarter wavelength at a frequency of operation and having formed on an interior surface thereof an array of conductive strips oriented by 45 degrees relative to the incident ray polarization. A conductive ground layer is formed on an exterior surface of the substrate, wherein radiation reflected by the ground layer and passing through the dielectric substrate is shifted by 180 degrees in phase and is rotated in polarization when combined with energy reflected from the conductive strip array by 90 degrees relative to radiation incident on the twist reflector.

Abstract: A device for receiving and/or transmitting an electromagnetic oscillation is described utilizing an antenna element and at least two wave-guiding assemblies which are each connected to a connection point of the antenna element via a respective supply device, and which are otherwise mutually insulated with respect to the electromagnetic oscillation. Each assembly comprise a conductor part which is coupled to the associated supply device in each of the wave-guiding assemblies for the transmission of the electromagnetic oscillation. The wave-guiding assemblies are designed for receiving and/or transmitting the electromagnetic oscillation via the supply device, and the conductor parts are constructed for receiving and/or radiating the electromagnetic oscillation in a manner comparable to the manner in which the antenna element operates. This device has a plurality of antennas without an appreciable increase in expenditure compared with a similar device having a single antenna element.

Abstract: A spaceborne hybrid antenna reflector for dual frequency band illumination of common spot beam coverage regions contains an interior solid reflector region, that is adjacent at its perimeter to a ring-shaped exterior dichroic reflector region and adjoined by a common backing structure. The solid interior region is reflective to RF energy at each of first and second spaced apart frequency bands, while the exterior dichroic reflector region is reflective at the first frequency band, but non-reflective at the second frequency band. This allows the hybrid reflector to realize the same beamwidth coverage for a transmitter operating at one frequency band and a receiver operating at the other frequency band. The backing support frame at the rear side of the reflector is electrically decoupled from the exterior dichroic ring.

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: A waveguide antenna assembly includes a feedhorn having a cavity coupled to a waveguide polarizer. The waveguide polarizer includes a single aperture waveguide, septum-loaded waveguide, and a dual aperture waveguide coupled inline. The septum-loaded waveguide includes an internal septum and is formed from at least one internal wall having a varying thickness. The length of the circular feedhorn and the diameter of the feedhorn cavity can be adjusted with the length of the single aperture waveguide to maximize signal isolation between the orthogonal signal ports.

Abstract: Circuitry for adjusting the resonant frequency of an Yttrium-Iron-Garnet (YIG) filter in the first local oscillator of a receiver carried on a guided missile is shown to include the combination of a crystal oscillator which produces a pilot signal for tuning the YIG filter to a corresponding resonant frequency and a frequency adjusting arrangement for offsetting the resonant frequency of the YIG filter by a predetermined amount.