Abstract: An improved millimeter wavelength antenna assembly having an input signal coupler, a dielectric waveguide, and a rotatable drum is disclosed. The input signal coupler reduces VSWR return losses and scattered radiation losses from the drum and matches a feeding waveguides characteristics to the dielectric waveguide. Embodiments of the invention include a reflector and a cylindrical lens to direct and form electromagnetic energy radiated by the antenna assembly.

Abstract: A compact high efficiency waveguide feed for reflector antennas includes a dielectric loaded aperture at its end for radiating energy to the reflector. The feed comprises a circular waveguide that carries the dominant TE11 mode, and terminates in a dielectric rod with an end cap. The exposed length of the dielectric rod between the end cap and the waveguide end constitutes a cylindrical aperture that radiates towards the reflector. The end cap and dielectric aperture dimensions are optimized for reflector high efficiency. Its small diameter provides an extremely compact feed, which reduces the sidelobes and operates well with both deep and shallow reflectors. As a result, high efficiency and low sidelobe performance can be obtained with symmetric centre fed reflectors.

Abstract: A dielectric fill disposed in a waveguide is used to form an antenna feed. One attribute of the dielectric fill is to enable a reduction in aperture size that in turn increases the beamwidth. More specifically, an RF signal received or transmitted at the end of the waveguide can have a wider half-power beamwidth angle than otherwise achieved without the dielectric filling the waveguide. A portion of the dielectric fill may protrude beyond the end of the waveguide to match the waveguide to free space. If the waveguide section is cylindrical in cross-section, a transformed section formed of an annular dielectric ring may be used to match the feed to a rectangular waveguide.

Abstract: According to the invention, a multi-beam radar sensor for microwaves is proposed, in which between a lens and the transmitter/receiver elements (6), focusing bodies (1) are disposed in such a way that they prefocus the radiation of an applicable transmitter/receiver element (6) with respect to the dielectric lens (8). The focusing bodies (1) are retained by a dielectric plate (2), into which a mount (4) is inserted. The mount (4) is embodied with regard to its material and geometric dimensions such that the least possible coupling between the individual focusing bodies (1) occurs. To attain this object, the mount (4) is embodied by recesses (5) in the regions between the focusing bodies (1). For simpler assembly and adjustment, bores (3) and adjustment openings (10) are provided.

Abstract: The present invention provides a dielectric leaky-wave antenna having a single-layer structure which is effective for realizing a highly efficient low-cost antenna in a quasi-millimeter wave zone in particular. This dielectric leaky-wave antenna includes a ground plane, a dielectric slab which is laid on one surface of the ground plane and forms a transmission guide for transmitting an electromagnetic wave from one end side to the other end side between itself and the ground plane along the surface, perturbations which are loaded on the surface of the dielectric slab along the electromagnetic wave transmission direction of the transmission guide at predetermined intervals and leak the electromagnetic wave from the surface of the dielectric slab, and a feed which supplies the electromagnetic wave to one end side of the transmission guide.

Abstract: An approach for providing a multiple-beam antenna system for receiving and transmitting electromagnetic signals from a plurality of closely spaced satellites is disclosed. Dielectric inserts are selectively coupled to the feedhorn bodies to alter the radiation patterns according to dielectric constants of the dielectric inserts. A reflector produces multiple antenna beams based upon the altered radiation patterns of the feedhorn bodies. The antenna provides simultaneous transmissions to satellites that are spaced about 2° or less.

Abstract: A radiation section of a dielectric feeder protrudes from an opening of a waveguide to improve the efficiency of receiving radio signals. An opening is provided at one end of the waveguide. A dielectric feeder held within the waveguide has a radiation section protruding from the opening. An annular wall having a bottom surrounds the opening of the waveguide. The depth of the annular wall is about ¼ of the wavelength of radio waves, and the width of a bottom surface of the annular wall is about ⅙ to {fraction (1/10)} of the wavelength of the radio waves. Consequently, the phases of a surface current that flows from the opening toward the bottom surface of the annular wall and a surface current which flows from the bottom surface of the annular wall toward the open end are substantially out of phase. As a result, the side lobes of the received radio signals are greatly reduced, and the gain of the main lobe is increased, improving the reception of radio waves transmitted from a satellite.

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: 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). The object is achieved by virtue of the radiating element (4) being arranged at an angle to the back wall (6) of the waveguide (5) or to a plane of the waveguide (5) which is parallel to the back wall (6).

Abstract: In a satellite broadcast reception converter, probes are equipped in a circular hole formed in a first circuit board, and plural fixing holes are formed around the circular hole. Snap pawls are formed at the open ends of the waveguides formed of sheet metal. The respective snap pawls are inserted in the fixing holes of the first circuit board so as to project to the back surface side of the first circuit board, and the fixing holes of the short caps are snapped into the snap pawls, whereby the first circuit board 6 is pinched and fixed between the waveguides and the short caps.

Abstract: Each of a first minute radiation pattern and a second minute radiation pattern is provided on a first circuit board so as to be inclined electrically by about 45° from the respective axial lines of a first probe for vertically polarized waves and a second probe for horizontally polarized waves. The first minute radiation pattern is approximately perpendicular to a phase conversion portion of a first dielectric feeder, and the second minute radiation pattern is approximately parallel with a phase conversion portion of a second dielectric feeder. The phase conversion portion of the first dielectric feeder is longer than that of the second dielectric feeder.

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. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Abstract: A dielectric slab is arranged on one surface of a ground plane to form a transmission guide for transmitting an electromagnetic wave along the surface from one end to the other end between the dielectric slab and the ground plane. A perturbation is loaded on the dielectric slab to leak the electromagnetic wave from the surface of the dielectric slab. A feed supplies an electromagnetic wave to one end of the transmission guide formed by the ground plane and dielectric slab. A dielectric layer is interposed between the ground plane and the dielectric slab, and has a lower permittivity than that of the dielectric slab.

Abstract: A primary radiator including a waveguide formed by winding a metallic plate into a cylindrical shape and superimposing both ends thereof at a joining portion. Two first flat portions and two second flat portions, extending in the direction of the central axis of the waveguide, are formed so that a first flat portion and a second flat portion alternate at intervals of substantially 90 degrees, thereby forming a total of four flat portions. A dielectric feeder includes a radiator section, an impedance converting section, and a phase converting section.

Abstract: The invention relates to an antenna structure for radiating electromagnetic waves in predetermined polarization configurations. A dielectric substrate is provided with a copper conductive pattern printed on each side. The conductors act as scattering elements and are printed for scattering radiation provided along a first predetermined feed direction or alone a second feed direction independently. Preferably, the pattern of the copper is based on an interference pattern and two feeds are used, one to provide radiation along each of the two feed directions. When used as a traveling wave antenna, the resulting structure is flat, having a low profile, and lightweight with simple electronics. Improved isolation Occurs when the printed interference patterns each contain only a component along a single direction such that each scattering element is linear and is parallel to or orthogonal to other scattering elements.

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 thermally cured polyimide is provided, and in particular a crosslinked polyimide, comprising a fluorenyl diamine and comprising an aromatic ring having at least one C1-C10 branched or unbranched alkyl substituent, where the alkyl substituent includes a benzylic hydrogen. The present invention provides a crosslinked polyimide made by a process comprising the step of crosslinking a polyimide comprising diamines comprising pendent fluorenyl groups and comprising aromatic rings having at least one C1-C10 branched or unbranched alkyl substituent, the alkyl substituent including a benzylic hydrogen, by raising the temperature of said polyimide above its glass transition temperature.

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: An element of a gigahertz electronic device is provided comprising a polyimide selected to have an imide equivalent weight of 375 or greater. The polyimide preferably has a dielectric loss at 12.8 GHz of 0.009 or less and a Tg of 260° C. or greater. Such elements include circuit substrates and antennas.

Abstract: A high frequency ceramic compact includes Al, Ti and Mn as metallic elements and contains substantially no Al2TiO5 phase as determined by X-ray diffraction analysis and is obtained by firing at about 1310C or lower. A preferred high frequency ceramic compact is represented by the following formula and has a Q-value at 10 GHz of 10,000 or more: (100−x−y)AlO3/2−xTiO2−yMnO, wherein x and y are % by mole and x and y satisfy the following conditions: 3.0≦x≦9.0; and 0.1≦y≦1.0. These high frequency ceramic compacts have a relative dielectric constant of 20 or less, a Q-value at 10 GHz of 10,000 or more, and can optionally control the temperature coefficient of resonant frequency around 0 ppm/° C.

Abstract: A device for directionally emitting and/or receiving electromagnetic radiation includes at least one printed circuit board having at least one transmitting/receiving element, at least one focusing dielectric lens, and at least one additional prefocusing body, which is positioned between the transmitting/receiving element and the dielectric lens. A cover is positioned in the plane between the transmitting/receiving element and the dielectric lens, the cover having at least one bushing for the additional prefocusing body, and the cover surrounding and fixing in place the additional prefocusing body held in the bushing.

Abstract: An antenna feeder line of the invention comprises a dielectric substrate, a first main conductor layer, a second main conductor layer, through conductor groups in two rows and sub conductor layers, which form a dielectric waveguide line, wherein a slot is provided in the first main conductor layer of the dielectric waveguide line, high-frequency signals are fed to an antenna device disposed above the slot, and a grounding conductor comprising a conducting bar and/or a conductor layer, for electrically connecting the first and second surfaces constituting H surfaces is disposed in a position which is perpendicular to a signal transmission direction and at a distance substantially not more than ½ the distance between E surfaces from side surfaces constituting the E surfaces, in a transmission area within a distance substantially the same as the signal wavelength from the slot to the input side or the side opposite thereto.

Abstract: An antenna. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Abstract: A primary radiator has a dielectric feeder at an open end of a waveguide in which the total length of the dielectric feeder is reduced. The dielectric feeder includes a holding portion forced into the interior of the open end portion of the wave guide and a radiation portion protruding outwardly from the open end of the wave guide, at least one recess being formed in each end surface of the two portions. The recess includes a stepped hole composed of a large diameter cylindrical hole and a small diameter cylindrical hole connected to the bottom surface thereof, the depth of each cylindrical hole being approximately ¼ of the wavelength &lgr;&egr; of the radio wave propagated through the dielectric feeder.

Abstract: A non-radiative hybrid dielectric line transition permits a line transformation between two different types of non-radiative dielectric lines to be performed in a limited space. In addition, a non-radiative dielectric line component, an antenna apparatus, and a wireless apparatus include the above line transition. In this structure, a dielectric strip is disposed between a lower conductive plate and an upper conductive plate to form each of a hyper NRD waveguide (HNRD) and a normal NRD waveguide (NNRD). Between the two waveguides, grooves whose depths gradually become shallow from the HNRD to the NNRD are formed for receiving a third non-radiative dielectric line for performing a line transformation.

Abstract: A dielectric resonator antenna having a resonator formed from a dielectric material mounted on a ground plane with a conductive skirt. The ground plane is formed from a conductive material. First and second probes are electrically coupled to the resonator for providing first and second signals, respectively, to or receiving from the resonator. The first and second probes are spaced apart from each other. The first and second probes are formed of conductive strips that are electrically connected to the perimeter of the resonator and are substantially orthogonal with respect to the ground plane. A dual band antenna can be constructed by positioning and connecting two dielectric resonator antennas together. Each resonator in the dual band configuration resonates at a particular frequency, thereby providing dual band operation. The resonators can be positioned either side by side or vertically. Further advantage is obtained by mounting the dual antenna stack within a radome.

Abstract: It is an object of the invention to provide a connection structure for connecting the dielectric strip of an NRD guide with a metal waveguide, in which the conversion loss (connection loss) for high-frequency signals is reduced, and in which the NRD guide as well as the millimeter wave integrated circuit in which the NRD guide is incorporated can be made smaller. A non-radiative dielectric waveguide is made by arranging a dielectric strip for propagating high-frequency signals between parallel planar conductors arranged at a spacing of not more than half the wavelength of a high-frequency signal, a conductive member being arranged at an end face of a terminal end of the dielectric strip. An aperture is formed in at least one of the parallel planar conductors at a location where the electrical field of an LSM mode stationary wave propagating along the dielectric strip becomes largest. An open terminal end of a metal waveguide is connected to this aperture.

Abstract: A dielectric resonator antenna has a dielectric layer and a conducting layer formed on a main surface of the dielectric layer. An electrical contact is formed on the main surface for connecting the dielectric layer to a transmission line for transferring a signal between the dielectric layer and the transmission line. The electrical contact is insulated from the conducting layer. A conducting strip is connected to the electrical contact and is on a side surface of the dielectric layer. The side surface is not on the same plane of the main surface. Rather, the side surface is perpendicular to the main surface of the dielectric layer.

Abstract: The present invention provides a planar antenna which has a decreased transmission loss, improved aperture efficiency, increased productivity, and reduced cost when it is used in a high-frequency band such as submillimeter and millimeter wave bands, and which allows multibeam scanning and electronic-beam scanning with a thin, simple structure. According to one aspect of the present invention, the planar antenna includes a planar ground conductor, a plurality of radiating dielectrics arranged in parallel and at established intervals on a surface of the ground conductor, and a plurality of perturbations for radiating an electromagnetic wave.

Abstract: A radiation section of a dielectric feeder protrudes from an opening of a waveguide to improve the efficiency of receiving radio signals. An opening is provided at one end of the waveguide. A dielectric feeder held within the waveguide has a radiation section protruding from the opening. An annular wall having a bottom surrounds the opening of the waveguide. The depth of the annular wall is about ¼ of the wavelength of radio waves, and the width of a bottom surface of the annular wall is about ⅙ to {fraction (1/10)} of the wavelength of the radio waves. Consequently, the phases of a surface current that flows from the opening toward the bottom surface of the annular wall and a surface current which flows from the bottom surface of the annular wall toward the open end are substantially out of phase. As a result, the side lobes of the received radio signals are greatly reduced, and the gain of the main lobe is increased, improving the reception of radio waves transmitted from a satellite.

Abstract: A dielectric slab is arranged on one surface of a ground plane to form a transmission guide for transmitting an electromagnetic wave along the surface from one end to the other end between the dielectric slab and the ground plane. A perturbation is loaded on the dielectric slab to leak the electromagnetic wave from the surface of the dielectric slab. A feed supplies an electromagnetic wave to one end of the transmission guide formed by the ground plane and dielectric slab. A dielectric layer is interposed between the ground plane and the dielectric slab, and has a lower permittivity than that of the dielectric slab.

Abstract: The present invention relates to an antenna device comprising a dielectric substrate 11;61 having at least one electrically conductive layer, a feeding 19 and a grounding 18 point. The antenna device is provided with a slot 14;71;81;91 having a closed path between an outer conductive region 12 and an inner 13 conductive region and is further provided with a feed slot 17;41;82;92;104 arranged at a first side of said closed slot 14;71;81;91, extending from said closed slot and outwards. A feeding means 2 is arranged to be connected to said feeding point 19 provided on said outer electrically conductive region 12 on a first side 15;16;73 of said feed slot 17;41;82;92;104, and a grounding means 3 is arranged to be connected to said ground point 18 provided on said outer electrically conductive region 12 on a second side, opposite to said first side, of said feed slot 17;41;82;92;104. The present invention also relates to an antenna assembly 110,120,130.

Abstract: Choke-ring ground planes are commonly used for multipath rejection in geodetic surveying systems. Such ground planes consist of a thick metal disc with deep grooves on one of the flat surfaces. An antenna is mounted in the center of the grooved surface. Known ground planes used in dual frequency communication systems (L1 and L2) could not be constructed to have good rejection of multipath signals in both L1 and L2 frequencies; instead, they are constructed for good rejection of multipath signals in L2 but not good for the rejection of multipath signals in L1. A first invention provides for equally good multipath rejection for both L1 and L2 frequencies by incorporating novel electromagnetic filter structures within the choke-ring grooves. The filter structures of the present invention enable the choke ring to provide multipath rejection in each frequency band which is as good as, or better than, the multipath rejection achieved in the L2 band with existing devices.

Abstract: An antenna. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Abstract: A scanning antenna includes a cylinder coupled to a dielectric waveguide into which an electromagnetic wave is launched. The cylinder includes rows of features such as recesses or stubs of differing vertical dimensions and periods. The cylinder when rotated directs the coupled radiation over a range determined by the periods of features in the rows and the rotation of the cylinder. Both transmitters and receivers are described. Benefits are described in connection with different cross section geometries to the waveguide. Also, both linear and circular polarization operations are described.

Abstract: A polyrod antenna fed at an end by a flared notch antenna. The space required to feed the polyrod is reduced, and a broader operating bandwidth is achieved. Gain of the antenna can be increased by increasing the polyrod length. A number of the polyrod antennas can be packed together in an array configuration.

Abstract: A continuous transverse stub element array structure which forms a coaxial geometry formed from a plurality of cylindrical segments, wherein each of the cylindrical segments has a rim at a top end and a bottom end, wherein each rim extends transversely away from the cylindrical segment relative to a longitudinal axis thereof to thereby form a stub element, wherein the individual cylindrical transverse stub elements are aligned end-to-end to thereby form a coaxial cable structure which surrounds a central core material. The series of these stubs form reactive or radiating elements for microwave, millimeter-wave, and quasi-optical filters and antennas. Purely reactive elements are formed by leaving the conductive coating on the terminus of the stub elements, whereas radiating elements are formed when stub elements of moderate radius are opened to free space.

Abstract: An electronically scanned antenna that is manufactured using semiconductor material and device fabrication technology. The antenna has a semiconductor substrate having a plurality of stubs projecting from one surface. The semiconductor substrate may be silicon, gallium arsenide, or indium phosphide, for example. A first conductive layer formed on the surfaces of the semiconductor substrate and along sides of the stubs so that the stubs are open at their terminus. The conductive layers form a parallel plate waveguide region. A diode array having a plurality of diode elements is formed in the semiconductor substrate that are disposed transversely across the semiconductor substrate and longitudinally down the semiconductor substrate between selected ones of the plurality of stubs. The diode array may comprise an array of Schottky or varactor diodes, for example.

Abstract: A wideband antenna element includes a conductive plate parallel to, and spaced from a ground plane. A tapered dielectric material is positioned between the plate and ground plane. A pair of driving points to the plate are positioned fixed distances on either side of a center interconnect point between the plate and ground plane, to effect staggered tuning of the antenna element.

Abstract: A dielectric resonator antenna having a resonator formed from a dielectric material mounted on a ground plane. The ground plane is formed from a conductive material. First and second probes are electrically coupled to the resonator for providing first and second signals, respectively, to or receiving from the resonator. The first and second probes are spaced apart from each other. The first and second probes are formed of conductive strips that are electrically connected to the perimeter of the resonator and are substantially orthogonal with respect to the ground plane. The first and second signals have equal amplitude, but 90 degrees phase difference with respect to each other, to produce a circularly polarized radiation pattern. A dual band antenna can be constructed by positioning and connecting two dielectric resonator antennas together. Each resonator in the dual band configuration resonates at a particular frequency, thereby providing dual band operation.

Abstract: An antenna for a radar unit for level measurement has a dielectric rod radiator for radiating microwaves in a main radiation direction. A coupling sleeve is provided with an external thread for installation by screwing into a holder opening. The coupling sleeve contains an at least partially approximately hollow cylindrical inner part made of dielectric material that projects in the main radiation direction out of coupling sleeve. A hollow guide system includes an HF coupling device and hollow guide tube that is received in an inner part. As viewed in the main radiation direction, the rod radiator is located releasably or permanently at the forward end of the inner part.

Abstract: A device is provided for fastening an excitation element (2) in a metal waveguide (3) of an antenna (1) and for electrically connecting the same to a coaxial line (4) arranged outside the waveguide (3), and which is cost effective and in which low power losses occur. The device comprises a basic member (6), which seals an opening in the waveguide (3), has a bore (6.1), and a metal hollow cylinder (9), through which an inner conductor of the coaxial line (9) is guided, which hollow cylinder has a first section (9.1) plugged into the first bore (6.1), and which has a second section (9.2), over which an end region (10) of an outer conductor of the coaxial line (4) is pushed. A first end (2.1) of the excitation element (2) is fastened on one end (12) of the inner conductor.

Abstract: This invention discloses a novel design for receiving electromagnetic signals broadcasted from at least two of satellite clusters and collected by a single dish antenna. At least two signal feeds are used to feed the signals to a processing circuit. The processing circuit performs signal selection, amplification, and frequency conversion. Corrective lens are used to ensure uniform wavefront of the electromagnetic signals received by the signal feeds located farther away from the focal point of the dish antenna. A convenient adjustment device is provided for adjustment of the relative positions of the signals feeds to the dish antenna.

Abstract: A true-time-delay corporate feed that minimizes both scan- and frequency-dependent variations in driving point impedance by realizing and exploiting a folded ensemble of intentionally mismatched E-plane tee junctions, E-plane steps, and E-plane bends that are used to form the antenna feed. A selected arrangement of E-plane tee junctions, E-plane steps, and E-plane bends are interconnected between a line-source interface that receives RF power and a plurality of line-source interfaces that couple the RF power to radiating stubs of a continuous transverse stub antenna array. The impedance of the individual mismatched components are set to be essentially constant and purely real, such that the feed network ensemble behaves as a multi-stage transformer, efficiently matching dissimilar radiator (load) and line-source (source) impedances over a broad range of operating frequencies and scan angles.

Abstract: A user terminal (110) which comprises an electrically-controllable back-fed antenna (300, FIG. 3) is used for the formation of single and multiple beams. The electrically-controllable back-fed antenna comprises an RF power distribution/combination network (310), electrically-controllable phase-shifting elements (320), a control network (440, FIG. 4) and radiating/receiving elements (360). The control network is coupled to the electrically-controllable phase-shifting elements and is used for controlling the dielectric constant of dielectric material contained within the electrically-controllable phase-shifting elements. In a preferred embodiment, phase-shifting elements comprise waveguide sections containing at least one dielectric material, and the dielectric material includes a ferroelectric material, preferably comprising Barium Strontium Titanate (BST).

Abstract: A low profile ceramic choke for global positioning antenna systems having a ceramic ring with a plurality of concentric segments arranged in coaxial relationship about a center occupied by a circular antenna. The segments are spaced apart from each other and may be housed in a metal enclosure. The top surface of the ceramic ring and the enclosure are of frustro-conical configuration to provide for moisture elimination. The choke is less bulky and is smaller in size and the use of ceramic as a high dielectric constant material promotes fabrication by molding and mass production techniques.

Abstract: A low cost microwave antenna. Microwaves are radiated from or collected by a thin layer radiating-collecting microwave guide section in which a dielectric slab is sandwiched between a metallic bottom plate and a metallic radiating-collecting cover plate. The cover plate contains a large number of slots spaced to produce outgoing or define incoming microwaves beams having directions determined: (1) by the directions of propagation of microwave radiation within the radiating-collecting microwave section and (2) by the frequency of the radiation. In a collection mode, a microwave lens focuses microwave radiation propagating in the waveguide section at focal locations which are dependent on the direction of propagation of the radiation in the waveguide. Alternatively, in a radiation mode, the lens converts microwave energy broadcast from said focal locations into parallel beams propagating in the radiating-collecting microwave guide section.

Abstract: An antenna includes a substrate, a microstrip patch or a slot, a feed line connected to the microstrip patch or slot, and a diffraction grating modulator mounted on the substrate and formed with a spatial periodic structure. The microstrip patch or slot radiates and receives electromagnetic waves when a signal between the substrate and the microstrip patch or slot satisfies resonance conditions. The diffraction grating modulator diffracts the electromagnetic waves in a predetermined manner so as to improve antenna gain and side lobe bandwidth and modulate directionality of the antenna.

Abstract: A low profile, receiving and/or transmitting antenna is adapted to be mounted onto an interior portion of a building or other structure to receive or transmit radiation through a first dielectric material, such as a window, associated with the building or other structure. The antenna includes a receiving/transmitting horn filled with a second dielectric material and a surface for mounting the antenna to the first dielectric material so that the horn is disposed at a particular angle with respect to a surface of the first dielectric material. A matching layer may be disposed between the first dielectric material and the second dielectric material to provide for a reflectionless match between the first and second dielectric materials.