Trw Limited

Northrop Grumman Systems Corporation

Charles W Chandler

Ann L Peebles

Makkalon Em

Louis C Wilson

Te-Kao Wu

James L Wolcott

David L Brundrett

George H Simkins

Gregory P Krishmar-Junker

Gregory P Junker

John R Bartholomew, Iii

Romulo F J Broas

Shady H Suleiman

A waveguide horn antenna includes a horn-shaped body portion and one or more feed structures. Each feed structure includes feed locations positioned between spaced apart ends of the body portion according to short circuit locations of desired frequencies to facilitate propagation of electromagnetic energy at the desired frequencies. Multiple frequency bands can be supported with the antenna by employing more than one axially spaced apart feed structures having associated feed locations arranged along the body portion of the antenna.

Broadband waveguide horn antenna and method of feeding an antenna structure

An antenna system that employs an antenna element for both transmit and receive functions, where a dual band polarizer is used to convert linearly polarized signals to circularly polarized signals and vice versa for two frequency bands. The dual band polarizer includes a waveguide including corrugated structures extending from opposing sidewalls, where ridges in the structures extend perpendicular to the propagation direction of the signal. The height of the ridges taper from a lowest height at the ends of the waveguide to a largest height at the middle of the waveguide. The corrugated structures interact with the field components of the signal in the direction perpendicular to the ridges that cause that component to be delayed relative to the field components parallel to the ridges so that the signal changes accordingly and maintains the same magnitude.

Dual band frequency polarizer using corrugated geometry profile

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.

Dual frequency single polarization feed network

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a folded optics antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed is coupled to a feed network which acts to combine the illumination beams of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate predetermined location on the subreflector which directs the illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides adjacent, antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

Compact folded optics antenna system for providing adjacent, high gain antenna beams

A steerable antenna comprises a steerable main reflector and a stationary feed assembly and subreflector assembly configured in a side-fed configuration where the feed assembly is to a side of both the main reflector and the subreflector. The main reflector, subreflector and feed assembly together produce an antenna beam which is directed in a preselected direction by the main reflector. A gimbal is coupled to the main reflector for positioning the main reflector and scanning the antenna beam over a preselected coverage area while the feed assembly and subreflector remain substantially stationary.

Side-fed offset cassegrain antenna with main reflector gimbal

A frequency selective reflector is provided for use in an electromagnetic antenna system, wherein the frequency selective reflector reflects electromagnetic waves having two or more frequencies. The reflector includes an inner portion which has a reflective surface which will reflect at least first and second frequencies. The reflector also includes an outer portion which will reflect electromagnetic waves having the first frequency in substantially the same direction as electromagnetic waves of the first frequency reflected from the inner portion. On the other hand, the outer portion is constructed to prevent the constructive reflection of electromagnetic waves of the second frequency in the same direction as electromagnetic waves of the second frequency reflected from the inner portion. By setting the diameter between the inner and outer circuit portions to have a predetermined relationship to one another, the reflector's electrical size in terms of wavelength can be substantially equalized for the first and second frequencies so that the beam width of the radiation patterns for the first and second frequencies will be superimposed and substantially equal to one another.

Frequency selective reflector

An antenna for providing a first antenna pattern at a first frequency of operation and a second antenna pattern at a second frequency of operation from first and second RF signals, respectively. The antenna included a horn which is dimensioned to generate the first antenna pattern from the first RF signal. A conduit is located within the horn and is configured to propagate the second RF signal in a waveguide mode. A corrugated rod having a first and a second portion is associated with the conduit. The first portion of the rod is located inside the conduit and the second portion of the rod protrudes from the conduit into the horn. The rod is configured to be responsive to the second RF signal and is operative to transition the second RF signal from a waveguide mode to a surface wave mode and propagate the second RF signal in a surface wave mode along the rod. The rod is configured to generate a second antenna from the second RF signal propagating in a surface wave mode. The first antenna pattern has first antenna pattern characteristics and the second antenna pattern has second antenna pattern characteristics. Changes in the dimensions of the horn will alter the pattern characteristics of the first antenna pattern but will have substantially no effect on the characteristics of the second antenna pattern. Changes in the length of the first portion of the rod will alter the pattern characteristics of the second antenna pattern but have substantially no effect on the pattern characteristics of the first antenna pattern generated by the horn.

Multi-pattern antenna having independently controllable antenna pattern characteristics

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a offset gregorian antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed array is coupled to a feed network which acts to combine the illumination beams of clusters of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate predetermined location on the subreflector which directs the composite illumination beams and directed towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

Compact offset gregorian antenna system for providing adjacent, high gain, antenna beams

Providing a tapered surface reflectivity to the reflecting surface of the parabolic reflector in a parabolic antenna using resistive material reduces side lobes and produces steeper roll off in the principal lobe, permitting use in the antenna of a smaller diameter microwave feed than required by an antenna without that tapered surface resistivity and, effectively, emulates the latter antenna. As a consequence of the smaller feed diameter, multiple feeds may be positioned contiguously to form multi-beam antennas that produce contiguous beam patterns. A satellite cellular communications multi-beam antenna incorporating the invention achieves greater regional coverage of the Earth.

Resistive taper for dense packed feeds for cellular spot beam satellite coverage

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a front-fed dual reflector antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned in a predetermined contour. Each feed array is coupled to a feed network which acts to combine the illumination beams of clusters of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate predetermined location on the subreflector which directs the composite illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

Compact front-fed dual reflector antenna system for providing adjacent, high gain antenna beams

An antenna system comprising a feed array, a subreflector and a main reflector which are oriented to define a side-fed dual reflector antenna geometry. The feed array is comprised of a plurality of separate feeds which are aligned on a predetermined contour. Each feed array is coupled to a feed network which acts to combine the illumination beams of clusters of a preselected number of feeds to produce a plurality of composite illumination beams. Each composite illumination beam is directed to be incident upon a separate preselected location on the subreflector which directs the composite illumination beams towards the main reflector. Each composite illumination beam is reflected by the main reflector in a preselected direction so that each composite illumination beam forms an antenna beam that impinges a predetermined coverage area on the Earth. Each antenna beam defines a separate coverage cell in the coverage area, wherein the position and orientation of the feeds, the subreflector and the main reflector provides antenna beams over a full Earth field of view coverage area where each antenna beam is approximately symmetrically shaped.

Compact side-fed dual reflector antenna system for providing adjacent, high gain antenna beams

A horn antenna is provided which is capable of operating at a plurality of separate frequencies while providing substantially equalized E and H-plane patterns for each of the separate frequencies. The antenna includes a coupling portion to permit coupling to a communication device. An inner portion is coupled to the coupling portion, and includes a first choke having a depth which extends substantially parallel to a central longitudinal axis of the antenna and a width which extends in a radial direction of the antenna. The depth and the width of the first choke are set so that the first choke will operate at the first frequency. An outer portion is coupled to the inner portion, wherein the outer portion has a maximum diameter in the radial direction which is greater than the maximum diameter in the radial direction of the inner portion. The outer portion includes a second choke which also has a depth to extend substantially parallel to the central longitudinal axis of the antenna, and a width which extends in the radial direction. The depth and the width of the second choke are greater than the depth and the width of the first choke, and are set so that the second choke will operate at the second frequency. By virtue of the fact that the depths of the chokes extend in a direction substantially parallel to the longitudinal axis of the horn, the maximum electrical aperture of the antenna can be very close in size to the maximum physical diameter.

Dual depth aperture chokes for dual frequency horn equalizing E and H-plane patterns

An antenna feed horn (,) for a satellite antenna array that includes multiple chokes (,) that provide effective control of the horn aperture mode content to generate radiation patterns which substantially have equal E-plane and H-plane beamwidths, low cross-polarization, low axial ratio, and suppressed sidelobes. The chokes (,) are annular notches that have both radial and axial dimensions. Two chokes (,) are provided at an internal transition location between a conical profile section (,) and a cylindrical aperture section (,). Additionally, another choke (,) is provided in the aperture (,) of the horn (,), and two additional chokes (,) are provided proximate the aperture (,). The size and location of the chokes (,) are optimized for the desirable mode content at the frequency band of interest to allow the propagation modes to be properly phase oriented relative to each other so that the useful bandwidth of the signal is on the order of 10% or greater.

Multimode choked antenna feed horn

A multi-pattern antenna for providing a plurality of antenna patterns at different frequencies or polarizations from a single reflector body eliminates the need for multiple reflector antennas on a single spacecraft. The reflector antenna comprises a reflector body and an illumination source. The illumination source illuminates the reflector with a plurality of RF signals each of a preselected frequency or polarization. The reflector comprises a plurality of zones with each zone reflecting preselected RF signals. A plurality of antenna patterns are generated from the reflected RF signals. Each zone is sized to a preselected shape such that the antenna patterns have a desired shape or beamwidth characteristic.

Multi-pattern antenna having frequency selective or polarization sensitive zones

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

Growing community of inventors

San Gabriel, CA, United States of America

Charles W Chandler