Abstract: A broadband corrugated feed horn and flat top multiple beam antenna for use in satellite communication systems, and the like. The profile of corrugations of the horn is specially tuned or designed to flatten the aperture field distribution. As a result, the aperture efficiency increases, and the gain of the corrugated horn also increases. Also, the circular aperture and corrugated construction of the horn result in improved circular polarization characteristics. The flat top multiple beam antenna comprises an oversized reflector and a plurality of high efficiency feed horns that exhibit a flat top aperture field. The present high efficiency corrugated feed horns may be used in the flat top multiple beam antenna. The flat top multiple beam antenna has a reduced interference signal level, increased gain in the coverage area, and improved frequency reusability from a four-color to three-color configuration.

Abstract: A family of FE dielectric-tuned antennas and a method for frequency tuning a wireless communications antenna are provided. The method comprises: forming a radiator; forming a dielectric with ferroelectric material proximate to the radiator; applying a voltage to the ferroelectric material; in response to applying the voltage, generating a dielectric constant; and, in response to the dielectric constant, communicating electromagnetic fields at a resonant frequency. Some aspects of the method further comprise: varying the applied voltage; and, modifying the resonant frequency in response to changes in the applied voltage. Modifying the resonant frequency includes forming an antenna with a variable operating frequency responsive to the applied voltage. Alternately stated, forming an antenna with a variable operating frequency includes forming an antenna with a predetermined fixed characteristic impedance, independent of the resonant frequency.

Abstract: A family of FE dielectric-tuned antennas and a method for frequency tuning a wireless communications antenna are provided. The method comprises: forming a radiator; forming a dielectric with ferroelectric material proximate to the radiator; applying a voltage to the ferroelectric material; in response to applying the voltage, generating a dielectric constant; and, in response to the dielectric constant, communicating electromagnetic fields at a resonant frequency. Some aspects of the method further comprise: varying the applied voltage; and, modifying the resonant frequency in response to changes in the applied voltage. Modifying the resonant frequency includes forming an antenna with a variable operating frequency responsive to the applied voltage. Alternately stated, forming an antenna with a variable operating frequency includes forming an antenna with a predetermined fixed characteristic impedance, independent of the resonant frequency.

Abstract: Antennas and multiplexer structures are provided for establishing individual communication links with satellites that are located at geostationary positions in close angular proximity to one another. The antenna includes individual wave-guides where at least one of the wave-guides has a decreased dimension such that the wave-guides may be spaced in close proximity to each other to communicate with the satellites. For example, in one embodiment, the antenna includes at least one wave-guide that is a hollow metallic structure filled with a dielectric material. The dimensions of this wave-guide can be altered by changing the dielectric material used to fill the wave-guide. By using a dielectric material having an appropriate dielectric constant, the dimension of the wave-guide can be configured to allow the wave-guide to be spaced in close proximity to the other wave-guide.

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 antenna connected to a waveguide can be used for level measurements of a bulk material by measuring the reflection of microwave radiation radiated towards the surface of the bulk material. Condensate droplets forming on the antenna may produce higher modes and echoes in the microwave signal. The effect caused by droplets can be ameliorated by increasing the size of the antenna and the waveguide. To obtain a usable measurement signal, a compromise between reducing the interference from condensate droplets and optimizing the electrical characteristics has to be found. The invention is directed to a waveguide which is designed to propagate at a particular frequency only the fundamental mode, while the antenna itself is capable of supporting higher order modes. A taper which is a dimensioned so as to transmit only the fundamental mode of the microwave signal, is placed between the waveguide and the antenna.

Abstract: A family of FE dielectric-tuned antennas and a method for frequency tuning a wireless communications antenna are provided. The method comprises: forming a radiator; forming a dielectric with ferroelectric material proximate to the radiator; applying a voltage to the ferroelectric material; in response to applying the voltage, generating a dielectric constant; and, in response to the dielectric constant, communicating electromagnetic fields at a resonant frequency. Some aspects of the method further comprise: varying the applied voltage; and, modifying the resonant frequency in response to changes in the applied voltage. Modifying the resonant frequency includes forming an antenna with a variable operating frequency responsive to the applied voltage. Alternately stated, forming an antenna with a variable operating frequency includes forming an antenna with a predetermined fixed characteristic impedance, independent of the resonant frequency.

Abstract: An antenna feed in a satellite system that provides substantially equal E-plane and H-plane patterns. The feed includes outer and inner conductive walls that are coaxial, and define an outer waveguide therebetween and an inner waveguide within the inner conductive wall. The feed includes a first cylindrical waveguide section, a tapered waveguide section, and a second cylindrical waveguide section at the aperture of the feed. Downlink signals are in signal communication with the first cylindrical waveguide section so that the downlink signals are launched into the outer waveguide and out of the feed. Uplink signals received by the inner waveguide are directed to suitable uplink reception devices. One or both of the outer or inner conductive walls include an array of radially disposed iris pins at the aperture that interact with the uplink and/or downlink signals to provide beam symmetry or equal E-plane and H-plane patterns.

Abstract: A high-isolation broadband polarization diverse circular waveguide feed apparatus capable of supporting any arbitrary linear, right-hand circular, left-hand circular or elliptically polarized electromagnetic wave with desirable performance over a broad range of frequencies and small size is disclosed. The waveguide feed employs the combination of a symmetrical shaped conical frustrum waveguide and circular waveguide segments together with a novel arrangement of orthogonal and nonplanar electric field probes and radio frequency impedance posts to achieve broad bandwidth, low cross-polarization when operating in arbitrary linear mode, and high-isolation for rejection of undesired cross-polarization components when operating in circular or elliptical polarization mode. Details of a 10.95-12.7 gigahertz embodiment of the waveguide feed including dimensions are provided.

Abstract: The invention relates to a horn antenna for a radar-filling level measuring device having an antenna envelope (3) that comprises a flaring hollow space (4) of the antenna, in which a filling (10) is present at least in part filling up said hollow space (4) of the antenna, and having an encasing (10, 20) of a dielectric material and enclosing the outside of the antenna envelope (3) and closing the opening (3a) of the hollow space of the hollow space (4) of the antenna.

Abstract: The primary radiator comprises a circular waveguide having a cone-shaped horn portion at one end and an enclosing surface at the other end, and a first and second probes inserted into the waveguide through a wall thereof. A plurality of cutout portions are formed at an open end of the horn portion. Two or more pairs of cutout portions are disposed symmetrically with respect to an axis of the waveguide and a depth of each cutout portion is adjusted to be about one quarter of the wavelength of the radio wave &lgr;0 transmitted through the air. With such a configuration, the phase reversal of surface currents flowing through the cutout portions and an adjacent projecting portion (a portion without cutout portions) take place, and a side lobe of a radiation pattern can be reduced considerably.

Abstract: A primary radiator includes a waveguide holding a dielectric feeder on which a radiation part, an impedance-conversion part, and a phase-conversion part are integrally formed. The radiator part widens from the aperture of the waveguide, and the phase-conversion part intersects a probe at an angle of substantially 45 degrees. Also, on the impedance-conversion part, a pair of curved surfaces are formed converging in the direction from the radiator part to the phase-conversion part, the impedance-conversion part has a cross-sectional shape which includes an approximately quadratic curve, and the thickness of the dielectric feeder converges such that the thickness gradually decreases in the direction from the radiator part to the phase-conversion part.

Abstract: A conical horn antenna that yields performance substantially equivalent to, or even greater than, that of a corresponding corrugated horn antenna while being simple and inexpensive to manufacture and light in weight. The body portion of the conical horn antenna is a conical horn antenna with a flare break positioned with respect to a central axis. At the output aperture of the body portion, a structure is located. The structure is a series of parallel rings, concentric to the common central axis, that are made of an electrically conductive material, and that are spaced at intervals to form a dielectric region between each ring. The dielectric region may be vacuum, air, free space or may contain a dielectric material. Alternatively, the structure is a helical winding, made of electrically conductive material, that spirals outwardly away from the central axis and forms a dielectric region between the turns of the winding. In a variation, the helical coil winding is surrounded by a jacket of dielectric material.

Abstract: Quad ridged horn antennas which may be individually disposed at the focal point of a parabolic reflector, or in an antenna array of parabolic reflectors. In the field of satellite communications, focus-fed parabolic reflectors are required to be compact yet provide broadband signal services. As such, the antenna horn feed structure must be very compact and provide equally broadband services. In order to provide uniform excitation of a parabolic reflector antenna, the antenna must have equal beamwidths in the E plane and the H plane. The quad ridged horn antenna of the invention equalizes these beamwidths through of a conductive ring around the mouth of the horn antenna. Matching the E plane and the H plane beam widths results in uniform excitation of a parabolic reflector. The conductive ring is advantageously effective for exciting a reflector or an array of reflectors in two closely spaced bands, such as the Ku band.

Abstract: A ridged feed horn antenna for use in broadband satellite communications. This multi-ridged feed horn operates in a receive band of 10-13 GHz and a transmit band of 14-15 GHz. The ridged feed horn antenna comprises excitation conductors which excite the field between each of the ridges in the feed horn antenna. The excitation conductors are connected to each of the ridges. A waveguide, terminated at the back of the horn antenna, enables the ridges to guide the energy from their respective excitation conductors toward the mouth of the feed horn antenna. A planar balun and matching circuit, located at the back of the horn antenna, may be used to feed each of the excitation conductors. Furthermore, the cross-section of each excitation conductor is chosen so as to optimize horn antenna performance. Each excitation conductor extends outwardly from the back of the horn and is parallel to the longitudinal axes of the horn waveguide.

Abstract: In a primary radiator, a dielectric plate is fixed to the interior of a hollow first waveguide having, at one end, an opening shaped like a regular square, and is substantially orthogonal to two parallel sides of the opening. A second waveguide of rectangular cross section is coaxially connected to the other end of the first waveguide. A pair of probes are disposed at an angle of approximately 45° with respect to the dielectric plate so as to protrude from flat inner wall surfaces of the second waveguide toward the center axis.

Abstract: A microwave phase-shifter including a coupler in a waveguide form, at least one pair of phase-shifter cells, and a conductive strip positioned between each phase shifter cell and configured with a conductive plane to form a guided space where a wave cannot propagate. An incident wave entering a first input of the coupler is subdivided into two waves. Each of the waves are reflected on an elementary cell with identical phases to the incident wave and are recombined into a resultant phase-shifted wave prior to exiting the coupler by an output juxtaposed with the first input.

Abstract: A feed horn assembly has an elongated horn portion having an end aperture and a generally cylindrical metallic interior surface and an elongated dielectric rod portion substantially centered with respect to the horn portion and having an elongated tapered end part extending in the direction of the horn aperture is described. The same type of feed horn assembly with the cylindrical metallic portion removed so as to leave only the tapered dielectric rod to provide small blockage. The horn is designed so as to have a minimal diameter and length and yet can produce a symmetrical horn pattern with a substantially stationary phase center over a large bandwidth. The design procedure also allows maintenance of these symmetrical patterns over a large gain range (6 to 18 dbi).

Abstract: A conductive-transmission-line waveguide converter comprising a waveguide for transmitting an electromagnetic wave, a wiring board brought into contact with a side of the waveguide opposite to a side of the waveguide for inputting an electromagnetic wave, being oriented perpendicularly to a longitudinal axis of the waveguide, a first probe provided in an area on the wiring board inside the waveguide for taking in a first linearly polarized wave, and a second probe provided in an area on the wiring board inside the waveguide for taking in a second linearly polarized wave perpendicular to the first linearly polarized wave, wherein the first probe and the second probe are respectively created along mutually perpendicular first and second axis lines, which both pass through a cross point of the wiring board and the longitudinal axis of the waveguide, and a first center line passing through the middle of each transversal line segment of the first probe is shifted from the first axis line and a second center line p

Abstract: The invention relates to a radiating source for transmitting and receiving, intended to be installed on board a satellite to define a radiation pattern in a terrestrial zone, said source being intended to be disposed in or near the focal plane of a reflector associated with other sources corresponding to other terrestrial zones. The source includes a plurality of radiating apertures, each of which has an efficiency at least equal to 70%, and feed means for feeding said radiating apertures. The radiating apertures and their feed means are such that the energy radiated by all of the radiating apertures is practically limited to the corresponding reflector, at least for transmission.

Abstract: A high-power microwave antenna in which, in order to radiate a pulse (8), the antennas (4) of the high power microwave are actuated by a pulse-generating source (3) and are embodied normally as wire antennas, horn antennas or the like. In particular for HPM active systems (1) to be conveyed, the antenna aperture of the antenna (4) is limited by the geometric edge dimensions of a carrier system (2) for the HPM active system (1), which further leads to a reduction in the efficiency of the antenna (4). According to the present invention, the antenna (4) is integrated into an airbag (5) that is inflated for operational use and thereby simulate the antenna (4). The antenna airbag (5) is inflated near a target (100) onto which at least one pulse (8) must be radiated.

Abstract: The present invention provides various wave-guides and support structures that are used in conjunction with feed structures to form compact antennas. Specifically, in one embodiment, the present invention provides a wave-guide design used for connecting the feed of an antenna to various electronics, such as a transmitter or receiver. The wave-guide of this embodiment includes a first end for connecting to the feed and a second end for connection to either a transmitter, receiver, or other electronic components. Importantly, the body of the wave-guide extends in a direction towards the reflector of the antenna so that the second end of the wave-guide is positioned closer to the reflector than the first end of the wave-guide. As such, the transmitter or receiver that is connected to the second end of the wave-guide is located in close relationship with the reflector, thereby creating a compact, aesthetically pleasing antenna structure.

Abstract: The invention relates to an apparatus for transmitting radio-frequency signals using a signal generation unit (2), a signal line (3), a radiating element (4) and a waveguide (5) which is terminated in an end region by a back wall (6), where the signal generation unit (2) generates the radio-frequency signals, where the signal line (3) routes the radio-frequency signals to the radiating element (4), and where the radiating element (4) projects into the waveguide (5).

Abstract: A diagonal dual-polarized broadband horn antenna. The unique use of diagonal line ridges placed in the corners of the aperture of the diagonal dual-polarized broadband horn antenna. The sides of the diagonal dual-polarized broadband horn antenna are made of any number of materials including dielectric material or metallic material. The operating frequency range of one embodiment of the present invention is approximately 100 MHz to 18 GHz in one embodiment. The present invention is scaleable to allow operation at even higher and lower frequencies. This ability of the present invention to adapt to a number of frequency ranges allows application for a wide variety of electromagnetic testing applications. The use of the diagonal line ridges allows for a broadband horn antenna that is significantly more manageable that conventional broadband horn antennas, while offering operation at common frequency ranges.

Abstract: A horn has an input aperture and an output aperture, and comprises a conductive inner surface formed by rotating a curve about a central axis. The curve comprises a first arc having an input aperture end and a transition end, and a second arc having a transition end and an output aperture end. When rotated about the central axis, the first arc input aperture end forms an input aperture, and the second arc output aperture end forms an output aperture. The curve is then optimized to provide a mode conversion which maximizes the power transfer of input energy to the Gaussian mode at the output aperture.

Abstract: A horn antenna including first and second substrates having at least one first and at least one second horn shaped cavity formed in the first and second substrates, respectively. The horn shaped cavities taper from a narrow end and have a longitudinal axis along a plane parallel to a top surface of the first and second substrates. The second horn shaped cavity is disposed opposite the first horn shaped cavity and is a mirror image of the first horn shaped cavity. Internal surfaces of the first and second horn shaped cavities include a metalization layer. The horn antenna is fabricated by forming at least one mask having a longitudinally extending mask opening on the first and second substrates and preferentially etching the first and second substrate through the mask opening to form the first and second horn shaped cavities.

Abstract: A multimode horn used to feed an antenna includes a generally conical wall for transmitting and/or receiving an electromagnetic signal there through. The wall flares radially outwardly from a throat section to an aperture and defines an internal surface having a plurality of discontinuities formed thereon and made out of electrically conductive material. The geometry of the discontinuities are configured and sized for altering the higher order mode content of the signal to achieve a balance between a plurality of performance parameters of the antenna over at least one pre-determined frequency range of the signal. The discontinuities are selected from the group consisting of local smooth profile, step, corrugation and choke.

Abstract: A millimeter or submillimeter wavelength device including a substrate having a horn shaped cavity, and first and second extension layers formed on a top surface of the substrate adjacent to the horn shaped cavity. The first and second extension layers define additional opposed sides of the horn shaped cavity, channels, and walls of the waveguide. Internal surfaces of the horn shaped cavity, the channels, and the waveguide walls include a conductive layer. Two such structures, which are mirror images of each other, are joined to form a horn antenna with integrated channels and a waveguide. The device is fabricated by forming a resist layer on a substrate which includes a horn shaped cavity. The resist layer is etched to form a half horn antenna, channels and walls of a waveguide. Internal surfaces of the half horn antenna, the channels, and the walls of the waveguide are then metalized. Two such metalized structures are then joined to form a full horn antenna integrated with channels and a waveguide.

Abstract: When a converter 14 is rotated via a rotation mechanism 17, the arrangement inclination angle of two primary radiators 15a and 16b 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 16b 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 feeder horn intended particularly for two-way satellite communications equipment and including a central transceiver horn (10) and at least three separate measuring horns (11, 12, 13) placed symmetrically in relation to the feeder horn symmetry line (O), wherein all horns are produced mechanically in one and the same metal element (1) which includes a through-penetrating center opening (100) for the transceiver horn (10), a bottom-delimited opening (110, 130, 140) for each of the measuring horns (11, 12, 13), and a moat-like recess (104, 114, 124, 134) in the metal element (1) around each opening (100, 110, 120, 130) for insulating each horn electromagnetically in relation to other horns. The delimited opening (110, 120, 130) for each of the measuring horns in the metal element (1) is filled with dielectric material (1101, 1201, 1301).

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: A multi-step circular horn system may have several steps and may use more than one flared section based upon design considerations. In order to achieve high aperture efficiency, the aperture field distribution is close to uniform. For good cross-polar performance, the field distribution is circularly symmetric. Location and shape of the steps is determined by the wavelength of the signal being transmitted and the space constraints imposed by the antenna design. The step discontinuities generate desired modes of operation in the right proportion.

Abstract: A converter is provided for changing frequencies of received signals generated by a single receiving antenna, when it receives radio waves transmitted from two artificial satellites (i.e., BS and CS) located in the same direction seen from a receiving point, to convert the received signals into received signals for transmission, wherein the received signals after such frequency changes can simultaneously be transmitted to a terminal side by way of a single transmission line. A radio wave of a right-hand circularly polarized wave transmitted from a broadcasting satellite (BS) as well as a radio wave of a right-hand circularly polarized wave and a radio wave of a left-hand circularly polarized wave both transmitted from a communication satellite (CS) are all received by a single receiving antenna, and each of received signals resulting from those radio waves is converted into a received signal for transmission by a converter.

Abstract: The invention concerns an electromagnetic wave transmitter/receiver device, comprising a body (18), characterised in that it comprises in combination: a receiver plate (16) incorporated in the body (18) including a first array of n radiating elements (301, 302, 303, 304) with a microstrip structure for receiving electromagnetic waves; means for transmitting (19, 20, 22, 23, 24) electromagnetic waves with longitudinal radiation defining a radiation axis for transmitting electromagnetic waves, said means including excitation means (24) for exciting the longitudinal radiation means (19, 20, 22, 23); said radiation means being substantially of constant cross-section in the body (18), perpendicularly intersecting the receiver plate (16) in a circular aperture around which are symmetrically arranged said radiating elements (301, 302, 303, 304), said receiving and transmitting means being arranged such that their respective phase centres are substantially arranged in a so-called focusing zone.

Abstract: A coaxial cavity antenna including a cylindrical inner conductor sized for propagation of electromagnetic signals in a preselected frequency range. The coaxial antenna also includes a cylindrical outer conductor positioned coaxial with the inner conductor, and having a diameter larger than the inner conductor. The outer conductor has an aperture ring disposed at an end of the outer conductor. The outer conductor is positioned with respect to the inner conductor to form a cavity between the inner conductor and the outer conductor. The cavity is sized for propagating electromagnetic signals in the preselected frequency range. The coaxial cavity antenna also includes a plurality of aperture teeth radially oriented and disposed around the aperture ring, and an iris ring positioned inside the cavity at a predetermined distance from the aperture ring.

Abstract: An antenna for transmitting microwaves is provided, which radiates microwaves to be transmitted as far as possible uncorrupted into free space and operates in a low-loss manner, having a circular waveguide (13) short-circuited at the end on one side, in which circular waveguide a transmitting element (15, 33) for feeding in microwaves is arranged, a funnel-shaped horn (25) adjoining an open end of the circular waveguide (13), the radius of which horn increases in the direction facing away from the circular waveguide, and an insert (27) made of a dielectric, which insert has a first cylindrical section (29), which fills the circular waveguide (13), and which insert has a conical section (31), whose tip points in the direction facing away from the circular waveguide and whose base area has a diameter which is greater than a diameter of the cylindrical section (29).

Abstract: An planar ultra wide bandwidth (UWB) antenna that provides integration of electronics is disclosed. The antenna has a first balance element that is connected to a terminal at one end. A second balance element is connected to another terminal at one end. The second balance element has a shape that mirrors the shape of the first balance element such that there is a symmetry plane where any point on the symmetry plane is equidistant to all mirror points on the first and second balance elements. Each of the balance elements is made of a generally conductive material. A triangular shaped ground element is situated between the first balance element and the second balance element with an axis of symmetry on the symmetry plane, and oriented such that the base of the triangle is towards the terminals. Accordingly, the ground element and each of the balance elements form two tapered gaps which widen and converge at the apex of the ground element as the taper extends outwardly from the terminals.

Abstract: The present invention provides a primary radiator capable of achieving both loss reflection and low loss. A watertight cap made of a dielectric material having a relatively high dielectric constant is attached to an open end of a horn part continuing from a waveguide, a dielectric member made of a dielectric material having a lower dielectric loss than the watertight cap is disposed within the waveguide, and a projecting part integrally formed at an end of the dielectric member is extended to the inside of the horn part, whereby an end face of the projecting part is made to face the back of the watertight cap at a fixed interval.

Abstract: An antenna apparatus and method for building the antenna is disclosed. Impulse signals travel through a feed point of the antenna with respect to a ground plane. A geometric fin structure is connected to the feed point, and through a termination resistance to the ground plane. A geometric ridge structure connected to the ground is positioned with respect to the fin in order to receive and radiate electromagnetic energy from the impulse signal at a predetermined impedance and over a predetermined set of frequencies. The fin and ridge can be either a wire or a planar surface. The fin and ridge may be disposed within a radiation cavity such as a horn. The radiation cavity is constructed of stamped and etched metal sheets bent and then soldered together. The fin and ridge are also formed from metal sheets or wires. The fin is attached to the feed point and then to the cavity through a termination resistance.

Abstract: An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, which is particularly suitable for operation at low power, such as under 125 Watts, and emptying small size thruster components. The disclosed apparatus differs from a conventional Hall thruster, which has an annular geometry. The conventional annular design is not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume. The present invention discloses a cylindrical geometry Hall thruster, utilizing a ceramic channel, in which the center pole piece of the conventional annular design thruster is eliminated or greatly reduced. Also disclosed are means of accomplishing efficient operation of such a thruster by designing magnetic fields with a substantial radial component, such that ions are accelerated in substantially the axial direction.

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: In a primary radiator, a dielectric plate is fixed to the interior of a hollow first waveguide having, at one end, an opening shaped like a regular square, and is substantially orthogonal to two parallel sides of the opening. A second waveguide of rectangular cross section is coaxially connected to the other end of the first waveguide. A pair of probes are disposed at an angle of approximately 45° with respect to the dielectric plate so as to protrude from flat inner wall surfaces of the second waveguide toward the center axis.

Abstract: An integrated dual-directional feed horn, for receiving RF signals from two satellites in small angle, includes a LNBF (first low noise block with integrated feed) and a second LNBF. The antenna dish focus the received RF signals onto receipt points of the focus plane, and the two LNBFs receive focused RF signals. The first LNBF receives circular polarized waves from the BSS satellite. The second LNBF receives linear polarized waves from the FSS satellite. One characteristic of the invention relies on integrating two LNBFs and making the two LNBFs adjacent to each other in the direction of short axis. Accordingly, the two LNBFs receive RF signals from two satellites in small angle. Increasing the length of the long axis thereof increases the areas of the wave-guides. The signal gain and communication quality are obtained.

Abstract: A multimode horn used to feed an antenna includes a generally hollowed conical structure for transmitting and/or receiving an electromagnetic signal there through. The structure flaring radially outwardly from a throat section to an aperture has a pre-determined size and an internal wall with a plurality of discontinuities for altering the mode content of the signal to achieve a balance between a plurality of performance parameters of the antenna over a pre-determined frequency range of the signal. At least one performance parameter is from the group of horn on-axis directivity, horn pattern beamwidth, antenna illumination edge-taper, antenna illumination profile and antenna spill-over losses. The discontinuities are a combination of different local smooth profiles and/or steps and/or corrugations and/or chokes.

Abstract: An antenna apparatus includes two substantially parallel conductor plates, a dielectric strip held between the two conductors, an aperture formed on the upper conductor plate above the dielectric strip, and a matching section for matching impedance between the dielectric strip and the aperture. The matching section is integrated with the dielectric strip below the aperture, thus continuously connecting the matching section to the dielectric strip.

Abstract: To make optimum use of an available volume exhibiting in particular surfaces of small radius of curvature, with a view to housing electronic circuits therein, a stack (11) of layers of possibly different compositions (circuits, components, insulants, etc.) is made, these layers being parallel to the surface of largest dimension of this volume.

Abstract: An antenna apparatus that has an increased efficiency, and a method for increasing the efficiency of multi-mode antenna feed horns, is disclosed. The method comprises the steps of exciting, within the antenna, a desired transmission mode and an undesired transmission mode of the signal to be transmitted, and converting, within the antenna, power within the undesired transmission mode into power for the desired transmission mode of the signal to be transmitted. An antenna apparatus in accordance with the present invention comprises a feed horn having an input opening, an aperture, and a cavity, disposed between the input opening and the aperture, for suppressing an undesired transmission mode of the antenna and exciting a desired transmission mode of the antenna.

Abstract: A conductive-transmission-line waveguide converter comprising a waveguide for transmitting an electromagnetic wave, a wiring board brought into contact with a side of the waveguide opposite to a side of the waveguide for inputting an electromagnetic wave, being oriented perpendicularly to a longitudinal axis of the waveguide, a first probe provided in an area on the wiring board inside the waveguide for taking in a first linearly polarized wave, and a second probe provided in an area on the wiring board inside the waveguide for taking in a second linearly polarized wave perpendicular to the first linearly polarized wave, wherein the first probe and the second probe are respectively created along mutually perpendicular first and second axis lines, which both pass through a cross point of the wiring board and the longitudinal axis of the waveguide, and a first center line passing through the middle of each transversal line segment of the first probe is shifted from the first axis line and a second center line p

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: A dual band multimode coaxial antenna feed has an inner section of longitudinal hollow waveguide having first and second orthogonal mode transducers that interface first and second orthogonally polarized cylindrical waveguide TE11 mode signals lying in a first upper (e.g., Ka) frequency band. An outer coaxial waveguide section has a Potter horn surrounding the inner waveguide section, which terminates at a polyrod. The outer section includes third and fourth orthogonal mode transducers that interface orthogonally polarized coaxial waveguide TE11 mode signals lying in a second lower (e.g., X) frequency band. A tracking port coupled to the outer coaxial waveguide section provides an output representative of the difference pattern of the radiation profile produced by transverse electromagnetic TEM mode signals generated and propagating in the outer coaxial waveguide. A mode suppressor in the outer waveguide section adjacent its two orthogonal mode transducers locally suppresses TEM signals in their vicinity.