Abstract: A high directivity slot antenna is presented herein. A method can include receiving, through an aperture of an antenna, a first electromagnetic signal away from a direct path from a source of the first electromagnetic signal to an electrical element of the antenna—the aperture corresponding to a first opening of a central chamber included between portions of radio frequency absorbent material, and the electrical element corresponding to a second opening of the central chamber. Further, the method can include absorbing the first electromagnetic signal into a first portion of the portions of radio frequency absorbent material—the first portion comprising a baffle that is adjacent to a first segment of the radio frequency absorbent material, and the baffle comprising a metallic element that alters a radio frequency propagation of the first electromagnetic signal from the central chamber into the radio frequency absorbent material.

Abstract: A waveguide to parallel-plate transition is provided which includes a waveguide, an E-plane waveguide bend, an H-plane waveguide bend and a parallel-plate transmission line arranged in sequence. The E-plane waveguide bend is configured to bend a direction of a radio frequency (RF) field between the waveguide and the H-plane waveguide bend by approximately 90 degrees in an E-plane. The H-plane waveguide bend is configured to bend a direction the RF field between the E-plane waveguide bend and the parallel-plate transmission line by approximately 90 degrees in an H-plane, and the parallel-plate transmission line includes a slot through which the RF field can flow between the H-plane waveguide bend and the parallel-plate transmission line.

Abstract: A target antenna 4A to be measured and a measuring antenna 5 are placed within an anechoic chamber 1. A first azimuth angle plane radiation pattern S21(R,?,?) is measured using a network analyzer 7 with an elevation angle ? of the target antenna 4A fixed to a first angle ?1. Next, a second azimuth angle plane radiation pattern S21(R,?,?) is measured using the network analyzer 7 with the elevation angle ? of the target antenna 4A fixed to a second angle ?2 different from the first angle ?1 by 90 degrees. A radiation efficiency of the target antenna 4A is measured by integrating in a spherical shape the azimuth angle plane radiation patterns S21(R,?,?) at two planes.

Abstract: Electronic device antennas with multiple parallel plate sectors are provided for handling multiple-input-multiple-output wireless communications. Each antenna sector in a multisector parallel plate antenna may have upper and lower parallel plates with curved outer edges and a straight inner edge. A vertical rear wall may be used to connect the upper and lower parallel plates in each antenna sector along the straight inner edge. Each antenna sector may have an antenna probe. The antenna probe may be formed from a monopole antenna loaded with a planar patch. The planar loading patch may be provided in the form of a conductive disk that is connected to the end of a conductive antenna feed member. The conductive member may be coupled to the center conductor of a transmission line that is used to convey radio-frequency signals between the antenna probe and radio-frequency transceiver circuitry. The antenna sectors may have interplate dielectric structures.

Abstract: Systems and methods for providing an antenna enabling hemispherical coverage are disclosed. The system includes a conductive enclosure having an open portion and a closed portion. The system further includes a pair of perpendicularly-disposed dipole antennas. Each antenna of the perpendicularly-disposed dipole antennas includes a pair of conductors extending to a pair of tips disposed outside of the open portion of the conductive enclosure. The system further includes a hybrid coupler having a pair of output terminals coupled to each pair of conductors of each antenna of the perpendicularly-disposed dipole antennas. The hybrid coupler is configured to apply signals of equal magnitude to the each antenna of the perpendicularly-disposed dipole antennas that differ in phase by ninety degrees.

Abstract: Accuracy of derivation of local corrections to GPS signals for use for aircraft landing guidance is subject to effects of reflected multipath signals. Antennas with a near-spherical antenna pattern of right-hand circular polarization, except within a downward cone, provide suppression of reflected multipath GPS signals incident from all azimuth angles and all relevant elevation angles. For such an antenna a cylindrical top assembly may include spaced conductive disks with intermediate exciter members excited at increments of 90 degree phase and surrounded by a dielectric ring. A cylindrical base assembly may include signal absorbent top and side wall portions and a bottom conductive disk and may alternatively include a signal absorbent inner wall portion.

Abstract: Electronic device antennas with multiple parallel plate sectors are provided for handling multiple-input-multiple-output wireless communications. Each antenna sector in a multisector parallel plate antenna may have upper and lower parallel plates with curved outer edges and a straight inner edge. A vertical rear wall may be used to connect the upper and lower parallel plates in each antenna sector along the straight inner edge. Each antenna sector may have an antenna probe. The antenna probe may be formed from a monopole antenna loaded with a planar patch. The planar loading patch may be provided in the form of a conductive disk that is connected to the end of a conductive antenna feed member. The conductive member may be coupled to the center conductor of a transmission line that is used to convey radio-frequency signals between the antenna probe and radio-frequency transceiver circuitry. The antenna sectors may have interplate dielectric structures.

Abstract: An antenna system includes a reflector having a modified-paraboloid shape; and a multi-beam, multi-band feed array located at a focal point of the reflector so that the antenna system forms a multiple congruent beams that are contiguous. The system has a single reflector with non-frequency selective surface. The reflector is sized to produce a required beam size at K-band frequencies and is oversized at EHF-band frequencies. The synthesized reflector surface is moderately shaped and disproportionately broadens EHF-band and Ka-band beams compared to K-band beams. The synthesized reflector surface forms multiple beams each having a 0.5-degree diameter at K-band, Ka-band, and EHF band. The multi-beam, multi-band feed array includes a number of high-efficiency, multi-mode circular horns that operate in focused mode at K-band and defocused mode at Ka-band and EHF-band by employing “frequency-dependent” design for the horns.

Abstract: A method and apparatus are disclosed for forming an image from millimeter waves. A field of view scanned using two geometrically orthogonal, intersecting copolarized fan beams (110, 120) to receive millimeter wave radiation. The received millimeter wave radiation from said fan beams are then cross-correlated (250, 650). Also, a method and antenna (400, 610) for receiving millimeter wave radiation are disclosed. The antenna includes first and second fan beam antennas (410, 420) for receiving millimeter wave radiation and a filter (430, 440) for rotating polarization of incident millimeter wave radiation through 90 degrees received by the second fan beam antenna (410). The respective first and second beams (110, 120) intersect and are co-polarized and geometrically orthogonal to each other.

Abstract: An antenna in a radar level gauge for determining the level of the surface of a medium stored in a tank. The antenna has a first and a second electrically conductive layer, and between the conductive layers a dielectric layer. The second of the conductive layers is provided with a number of holes in a predetermined pattern. Leading to the center of the dielectric layer is a transmission line. The microwaves from a radar unit in the radar level gauge are supplied to the dielectric layer in the antenna via the transmission line and transmitted out in a radial direction from a feed point in the dielectric layer that acts as a waveguide. Via said holes in the second conductive layer a microwave beam radiates out. Due to matching of the phase of the microwave and the placing of the individual holes in the pattern that the holes form, a predominant waveguide mode of the desired order is obtained.

Abstract: A multi-band antenna with a reflector, comprising a box-shape reflector, wherein the box-shape reflector includes a base plate, a surrounding sidewalls and an extending plate, wherein the extending plate and the base plate are respectively attached on both sides of the surrounding sidewalls, thereby forming a box-shape with a receiving area on an inner surface of the base plate, and the extending plate is substantially parallel to the base plate; and a radiation unit coupled to the inner surface and substantially parallel to the base plate.

Abstract: In an exemplary apparatus implementation, an electromagnetic lens includes: an input section including multiple input probes and a curvilinear input reflector; an output section including multiple output probes and a curvilinear output reflector; and a coupling section including a coupling slot and a curvilinear coupling wall. In another exemplary apparatus implementation, an electromagnetic lens includes: a first layer; a second layer adjacent to the first layer; the second layer including multiple input probes, a curvilinear input reflector, and a first curvilinear coupling wall; a third layer adjacent to the second layer, the third layer including a coupling slot; a fourth layer adjacent to the third layer; the fourth layer including multiple output probes, a curvilinear output reflector, and a second curvilinear coupling wall; and a fifth layer adjacent to the fourth layer.

Abstract: An antenna directivity enhancer to enhance the directivity of an antenna is disclosed. The enhancer has a 3-dimensional structure in a predefined 3-dimensional shape when operating to enhance the directivity of an antenna. The 3-dimensional structure can be flexibly collapsible into 2-dimensional flat surfaces, with at least two of the surfaces not required to have any space between them when the structure is collapsed. The direction where the directivity is enhanced can be changed as desired. The enhancer can include just one reflecting surface, or at least two reflecting surfaces. In yet another embodiment, the enhancer includes a curved surface when the enhancer is in its predefined 3-dimensional shape.

Abstract: A shield for shielding radio frequency emissions being emitted from a communications antenna. The shield has a first layer of material having the physical property of generally absorbing radio frequency electromagnetic emissions and a second layer of material having the physical property of generally reflecting radio frequency emissions. The first layer of material is positioned between the second layer of material and the communications antenna. Therefore, the first layer of material absorbs a portion of the radio frequency emissions from the communications antenna, and the second layer of material reflects back the remaining emissions to the first layer of material. Therefore, the first layer absorbs a further portion of the remaining emissions. A layer of absorbing material is placed between the combined first & second layers and a material that is transparent to radio frequency emissions and through which the communications antenna radiates radio frequency energy.

Abstract: A hog-horn antenna for producing two orthogonally polarized signals. The elevation plane pattern of each signal can be made to have virtually any shape, but is typically of a substantially cosecant-squared shape. In providing for the dual-polarization capability, the hog-horn antenna is designed to produce substantially equal gains for orthogonal polarizations, either simultaneously or separately. Two techniques to substantially equate the elevation plane radiation patterns of the two polarizations include corrugating or absorber-lining the surfaces of portions of the hog-horn antenna. Azimuthal pattern control may be achieved by corrugated/absorber lined flanges.

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

Abstract: A sector beam antenna with a scattering component, in which a desired radiation pattern can be obtained, is provided. The sector beam antenna with the scattering component provides parallel plates composed of two conductive plates disposed in parallel in which the distance between the parallel plates is longer than a half wavelength and shorter than one wavelength of a using wavelength, a primary radiator block having an H bend function disposed between the parallel plates, an input port opened at one of the parallel plates in order to supply power to the primary radiator block, and a scattering component made of a conductive material and disposed in parallel to an aperture being an opening end of the parallel plates in a state that a designated distance exists between the scattering component and the aperture. With this structure, the radiation pattern radiating from the aperture can be formed freely.

Abstract: A parabolic horn antenna designed for use as a high isolation antenna array in a wireless Internet access system where a high concentration of transceivers at one location is required. The rear, reflecting surface of the horn part of the antenna is a parabolic shape with the probe located at the focal point of the parabola. The sides of the antenna in the broad dimension are angled at an optimum degree increasing the opening aperture allowing the system to capture more RF energy. The length, therefore the aperture width is variable providing control over the gain of the system thus providing effective shielding and isolation for more dense antenna arrays.

Abstract: Compact, microwave scanned antennas include combinations of a radiator, a reflector and a mirror. The radiator is formed by plating a shaped dielectric core. It generates an antenna beam at an output aperture in response to a microwave signal at an input port. The wavefront orientation of the antenna beam is a function of the wavefront orientation of the microwave signal at the input port. Changing the angular relationship between the path of the microwave signal and the input port changes the wavefront orentation of the antenna beam and, therefore, its beam axis. Pivoting the reflector realizes the desired angular change in the microwave signal path. Alternatively, the reflector can be fixed and the mirror pivoted to vary the microwave signal path. Antenna embodiments can be physically realized with a single moving part, the shaped dielectric is easy to form and when configured to operate at a high frequency, e.g., 77 GHz, the antenna is small enough to fit behind an automobile license plate.

Abstract: A compact microwave antenna suitable of printed-circuit fabrication is comprised of a non-radiating guided wave structure for supporting the propagation of captured surface-guided waves; a series of dipoles in proximity to the guided waves supported by the non-radiating guided wave structure, wherein such dipoles are excited by the guided waves, thereby generating a desired radiation field, wherein the dipoles are independent of electrical transmission lines, and wherein the length and spacing of the dipoles are selected to achieve a desired angle of radiation from the surface of the non-radiating guided wave structure and a desired radiation frequency; and excitation means, in communication with the non-radiating guided wave structure, for exciting the reactive medium with electromagnetic waves to generate the captured surface-guided waves.

Abstract: A directive communications antenna comprising upper and lower plates, each having a leading edge, and a parabolic reflecting cylinder disposed between and axially intersecting the plates so as to form a cavity having a focus line. The cavity is open adjacent the plate leading edges. Upper and lower lip plates respectively extend along the leading edges of the upper and lower plates with both lip plates projecting upwardly therefrom. A feed assembly comprised of a feed probe and a sub-reflector is positioned within the cavity.

Abstract: An array antenna is shown, the disclosed antenna having an effective cross-sectional area which is lower than its physical cross-sectional area. The reduction in effective cross-sectional area is effected by: (a) fabricating the reflector for the array antenna from spaced wires; and, (b) curving the entire array and its reflector.

Abstract: A primary radar antenna has a secondary radar antenna or an IFF antenna integrated therewith. Excellent properties with respect to compactness, radiation and frequency dependency are achieved by providing a bilevel pillbox antenna having radiation deflection on a cylindrical parabolic reflector from one interplate space to another. The lower interplate space has, in proximity of the primary radar signal radiator, which is arranged with its radiation center in the focal line of the parabolic reflector, an additional feed for in-coupling of the IFF signal. The antenna is particularly suited as a combined primary and IFF radar antenna for smaller vehicles.

Abstract: A primary radar antenna, designed as a pillbox antenna, has an IFF antenna integrated therewith. Excellent properties with regard to compactness, radiation and frequency dependency are achieved through the combination of a pillbox antenna with a multiple IFF antenna composed of a plurality of radiator elements, which is applied on the upper side of the pillbox antenna for radiation of the IFF signals. The antenna is particularly suitable as a combined primary radar/IFF antenna for smaller vehicles.

Abstract: A parallel-plane antenna of the pillbox or cheese type in which the cylindrical-parabolic portion is constituted by a semitransparent reflector and the focal plane of which is constituted by a polarizing reflector. The cylindrical-parabolic semitransparent reflector is constituted by an array of wires parallel to the plane of polarization of the wave emitted by the source. The polarizing reflector is formed by a reflecting plate located at a distance of .lambda./4 from an array of parallel wires inclined at 45.degree. with respect to the plane of polarization of the incident wave.

Abstract: The multiple beam, short wave planar antenna array system, which simultaneously exhibits low loss, low side lobe levels, high efficiency, and low volume in a design affording independent control of the E and H plane radiation pattern shapes is particularly applicable in microwave radiometric systems such as airborne mapping systems. The antenna system generates symmetrical, matching narrow pencil beam sensitivity patterns by using symmetrically spaced sectorial receiver horns fed energy through a hyperbolic dielectric lens, the horn array and lens residing in a TE.sub.01 mode parallel plate guide, the lens being illuminated by signals collected by a broad wall slotted wave guide array supplied with a thin, planar sheet radome mounted on the energy receiving face of the array.

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