Abstract: The present invention provides a high-performance helical antenna element and array thereof for use in an aircraft communication system or the like, where stringent spatial restrictions and gain requirements generally apply. The performance of the array is enhanced by connecting conductive plates to the windings of the antenna elements at the terminal ends thereof such that the conductive plates are offset from the axes of the antenna elements and toward the center of the array.

Abstract: The present invention provides a high-performance and lightweight helical antenna element and array thereof for use in an aircraft communication system or the like, where stringent spatial restrictions and gain requirements generally apply. The RF performance of the array is enhanced by using ribs and sleeves to reduce the dielectric volume of the support structures of the antenna elements, and by providing apertures within the sleeves of the support structures and between the ribs thereof.

Abstract: The present invention provides a high-performance and small sized helical antenna element and array thereof for use in an aircraft communication system or the like, where stringent spatial restrictions and gain requirements generally apply. The performance of the array is enhanced by increasing the lateral distances between the antenna elements over a portion of the elements where the windings thereof have high current amplitude. The sweeping envelope of the array is maintained small by recovering the initial distancing over a portion of the elements where the windings thereof have low current amplitude.

Abstract: The present invention provides a high-performance and small sized helical antenna element and array thereof for use in an aircraft communication system or the like, where stringent spatial restrictions and gain requirements generally apply. The performance of the array is enhanced by increasing the lateral distances between the antenna elements over a portion of the elements where the windings thereof have high current amplitude. The sweeping envelope of the array is maintained small by recovering the initial distancing over a portion of the elements where the windings thereof have low current amplitude.

Abstract: A single-structure, two-bit phase shifter useful for steering the beam of an antenna such as an aeronautical antenna. The phase shifter includes an input line, an output line, a plurality of switched lines such as quarter-wavelength microstrip lines connected directly or indirectly between the input line and the output line, and a plurality of switches for selectively and controllably connecting one or more of the switched lines between the input line and the output line. The phase shifter controllably connects one or more of the switched lines in series between the input line and the output line, thus providing phase shifts of an input radio frequency (RF) signal between one of four discrete phase shift amounts. Using up to three quarter-wavelength switched lines, the phase shifter provides phase shifts in increments of ninety degrees, e.g., phase shifts of zero, ninety, one hundred eighty, and two hundred seventy degrees (0°, 90°, 180°, and 270°).

Abstract: A method for improving the electric isolation of a wide coverage antenna mounted on a structure. The structure defines a peripheral wall and a first end wall and the elongated antenna has a base. The antenna pivotally mounts on the structure about a mounting axis parallel to the structure axis, in a spaced apart relationship relative to the peripheral wall in a direction pointing generally outwardly therefrom with the antenna base and at least part of an antenna body being in a step back relationship relative to the first end wall such that the antenna is at least partially electrically isolated by the structure while being substantially hidden from the first end wall. A second antenna similarly pivotally positioned relative to the peripheral wall can be generally opposed to the first antenna about the structure such that the two antennas are at least partially electrically isolated from one another.

Abstract: A dielectric resonator element array (DRA) antenna system that is small, compact, has high gain in the direction of intended communication, minimized interference in unintended directions of communication and a wide bandwidth. The antenna system comprises a ground plane, a feed structure, a beam shaping and steering controller, a mounting apparatus, an array of dielectric resonator elements and a radome that is close to or in contact with the array. The mounting apparatus preferably is configured so as not to appreciably increase the size of the system when mounted. The controller receives and processes information relating to one or more of object latitude, longitude, attitude, direction of travel, intended direction of communication and unintended directions of communication. The controller processes this information and determines excitation phase for the array elements.

Abstract: The present invention provides a dual antenna system where a first antenna element has a metallic surface with openings that are resonant at frequencies other than the operating frequency of a second antenna element. The openings are sized such that the metallic components are relatively transparent at and near resonant frequencies of those openings. According to the present invention, the resonant frequencies of the openings may be the transmitting or receiving frequencies of the second antenna element, or of nearby antennas.

Abstract: A drive mechanism for an antenna array mounted on a moving vehicle. The antenna array is mounted on a disc having two motors which, cooperatively, rotate the disc and rotate a number of antenna elements mounted on the disc. By rotating the antenna elements, the main lobe of the array may be scanned towards a satellite in the elevation plane. To track a moving source from a moving vehicle, one of the motors rotates the disc as a whole, thereby scanning the beam in the azimuth plane. Each antenna element is at an angle to the vertical so that, by rotating the disc to face the direction of the signal source, such as a satellite, a better signal can be obtained.

Abstract: A pentagonal antenna array having a high aperture efficiency and a suitably high overall gain and low antenna noise temperature. The high aperture efficiency of this antenna system provides an overall system capacity suitable for broadband communication services. The antenna array consists of five antenna elements each located at a separate vertex of a pentagon. The antenna elements are helical antennas to provide a narrow antenna beam width. The antenna array itself is supported on a base platter which may be steered to point at a satellite using conventional gimbal ring apparatus. The base platter is a planar reflector to reflect the antenna element radiation in the rear direction and thereby reduce the antenna backlobe levels. The input power and the signal transmitted are fed through a phasing/combining network. The phasing/combining network appropriately divides the signal and the input power and phases the signal, prior to feeding the signal to each of the five antenna elements.

Abstract: An antenna array of parabolic rectangular reflectors for use in satellite communications. The antenna comprises two parabolic reflectors disposed contiguously on a common outer surface. The common surface forms a continuous antenna aperture. The parabolic reflectors have rectangular side edges which permit the adjacent edges of the parabolic reflectors to be spaced closely. The mouth of each parabolic reflector is focussed on a separate feed. The focus of the feed is not located at the center of the reflector but rather offset. The antenna feeds and the reflector foci are displaced toward the center of the array such that the spacing between the antenna feeds is less than half the length of the antenna. The present invention provides the displacement of each reflector focal point and each antenna feed toward the center of the array.

Abstract: A phased-array antenna whose main beam can be positioned (scanned) substantially anywhere within a full hemispherical coverage. The phased-array antenna consists of a plurality of radiating multi-filar helix antenna elements, each of which is independently rotatable on its helix axis relative to the antenna base plane. The rotation of each radiating element substantially decreases the noise temperature, the passive intermodulation of signals, and the sidelobe levels relative to an antenna which uses PIN diode phase shifters. A change in the radiated signal phase of each element in the antenna array is achieved by the mechanical rotation of the multi-filar helical antenna element on its axis. Mechanical rotation is provided by a drive system or multiple drive systems coupled to at least one radiating antenna element. The drive system rotates the at least one radiating element on its axis by various amounts.

Abstract: A steerable antenna system for transmitting and/or receiving an electromagnetic signal to a relatively moving target includes a hyperbolic subreflector secured to a frame rotatably mounted on a support structure via a first motor and a feed source located at a first focus of the subreflector for illuminating the same. The source, fixed to the structure, has a source axis pointing at the subreflector. A parabolic reflector having a focus in common with the second focus of the subreflector to transfer the signal between the same and a planar reflector is secured to the frame and has a beam axis. The planar reflector having a normal axis intersecting the beam axis with an angle is rotatably mounted on the frame via a second motor to transfer the signal between the parabolic reflector and the target. The system may include a controller connected to the motors to control the system to steer at the target anywhere within a full spherical angular range.

Abstract: A drive mechanism for an antenna array mounted on a moving vehicle. The antenna array is mounted on a disc having two motors which, cooperatively, rotate the disc and rotate a number of antenna elements mounted on the disc. By rotating the antenna elements, the main lobe of the array may be scanned towards a satellite in the elevation plane. To track a moving source from a moving vehicle, one of the motors rotates the disc as a whole, thereby scanning the beam in the azimuth plane. Each antenna element is at an angle to the vertical so that, by rotating the disc to face the direction of the signal source, such as a satellite, a better signal can be obtained.

Abstract: The present invention provides a dichroic surface with a pointed resonator cross grid pattern that offers enhanced bandwidth and a sharper response between frequency bands. The dichroic surface is fabricated as a self-adhesive decal, conforming the dichroic surface to the surface of the reflector antenna.

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: An antenna comprising at least one dipole, the dipole comprising a pair of arms drooping relative to a plane orthogonal to a central axis, end portions of the arms being bent back toward the central axis. In one form of the invention the arms are bent back toward the central axis in at least one plane which is parallel to the central axis, and in another form of the invention the dipole arms are bent in the same rotational direction out of a pland which includes the central axis.

Abstract: An aircraft mounted antenna system comprising a plurality of linear blade antenna arrays mounted on an upper portion of an aircraft fuselage. The blade arrays are symmetrically placed on the fuselage about a plane vertically bisecting the upper portion of the fuselage. The placement of the blade arrays is such that large scanning angle gain losses are minimized as the blade arrays on one side of the fuselage hand off the satellite tracking, acquisition, and communication to the blade arrays on the other side of the fuselage as the scanning angle increases.

Abstract: An improved top fed quadrafilar helical antenna that provides circular polarization with near uniform gain over the upper hemisphere. The antenna comprises a pair of crossed printed circuit boards with two feed lines and two horizontal arms per board and four piecewise linear conductors. Each arm is connected to a feed line and to the end of a conductor that is piecewise linearly attached to the edges of the crossed printed circuit boards.

Abstract: An adjustable RF microwave tuning post for use in an RF cavity is disclosed. It is comprised of a flexible integrally-formed hollow tuning post disposed in the RF cavity. A drive shaft extending internally of the tuning post is provided to vary the dimensions of the tuning post. The drive shaft is connected to the tuning post at the top end thereof and connected at the other end of the drive shaft to an adjusting nut. The tuning post is made flexible by the use of bellows, which in a preferred embodiment of the invention is located along the side walls thereof.