Mcdonnell Douglas Corporation

Pacific Antenna Technologies, Inc.

General Atomics, Inc.

Coi Ceramics, Inc.

John R Glabe

Edward L Pelton

Francis D McGaffigan

Leland H Hemming

Thomas Barrett Jackson

Mark E Bonebright

Paul C Kuhl

Andrew B MacFarland

Daniel George Laramie

Curt Gibson

Systems and devices are disclosed for implementing a low profile antenna that can be mounted on various platforms or vehicles without significantly changing the appearance of the platform or vehicle. The disclosed technology can be used to construct low profile antennas to reduce the antenna thickness while maintaining high efficiency.

Low profile communications antennas

Radomes include an outer wall having a first average thickness and an inner wall having a second average thickness that is different from the first average thickness. At least a major portion of the inner wall is separated from at least a major portion of the outer wall by a space therebetween. The outer wall may comprise a layer of ceramic matrix composite (CMC) material. Aircraft and spacecraft include such radomes. Methods of forming radomes include forming an outer wall having a first average thickness, forming an inner wall having a different second average thickness, and coupling together the inner wall and the outer wall in such a manner as to provide a space between at least a major portion of the outer wall and at least a major portion of the inner wall.

Radomes, aircraft and spacecraft including such radomes, and methods of forming radomes

A single element, multi-frequency dipole antenna including two substantially equal arm sections of conductive material extending co-axially in a straight line in opposite directions from each other, each arm section being a mirror image of the other arm section throughout its entire length, each arm section including at least two contiguous shorter sub-sections of j.sub.1, j.sub.2, . . . j.sub.n lengths, wherein j.sub.1 represents the length of the innermost sub-section, sub-sections terminated by discontinuities wherein j.sub.1 represents the 1/4 wavelength of the highest resonant frequency and each consecutive-integer sequence of j sub-sections represent the 1/4 wavelength of lower resonant frequencies.

Single-element, multi-frequency, dipole antenna

A dual frequency feed element for a parabolic reflector antenna system, comprising a conductive cavity having a central axis, the cavity mounted at the focal point of a parabolic reflector surface and defined about its outer perimeter by an upstanding cavity wall, and having a closed cavity floor and an open top directed toward the reflective surface, a dual frequency radiating element centrally disposed in the cavity and arranged to radiate a first low frequency signal out through the cavity open top to the antenna surface, a conductive floor fixed below the radiating element a distance in relation to the radiant energy for the first low frequency signal, and disposed in the cavity transverse to the central axis thereof to reflect radiant energy for the first signal and, a frequency selective surface fixed below the radiating element, apart from the conductive floor, and transverse to the central axis of the cavity to reflect radiant energy for the second, higher frequency signal while simultaneously being invisible to the lower frequency signal.

Dual frequency reflector antenna feed element

A broadband flared slot notch antenna combined with an overhead metal plate resulting in an improved front-to-back ratio and a reduced response to crossed polarized radiation. The antenna is provided by a metal layer deposited on a dielectric substrate which is etched to form a pair of symmetrical slot sections having facing edges which increasingly curve away from each other to a maximum spacing point which is the antenna aperture. A linking slot interconnects the slot sections at a feed point spaced from the aperture. High frequency electrical voltage applied at the feed point achieves launch of an electromagnetic wave from the aperture. The overhead metal plate is parallel and closely spaced above and shorted to the antenna thereby reducing radiation emissions that are not in the direction of that launched from the aperture. The metal plate is shorted to the antenna along a line orthogonal and adjacent to the linking slot to prevent radiation from being launched in a direction opposite that described above. The forward edge of the metal plate is terminated with a tapered resistive card to prevent radiation scatter off the edge. The back portion of the space enclosed by the plane of the antenna and the metal plate may be filled with electromagnetic radiation absorbing material to further reduce such radiation. In addition, the sides of the metal plate, may be partially or completely closed with metal walls that are shorted to the metal plate for reducing radiation emissions that are orthogonal to that launched from the aperture.

Broad band parallel plate antenna

An antenna (10) is provided by a metal layer (12) deposited on a dielectric substrate (16) which is etched to form a pair of symmetrical slot sections (20,22) having facing edges which increasingly curve away from each other to a maximum spacing point which is the antenna aperture (26). A linking slot (32) interconnects the slot sections (20,22) at a feed point (30) spaced from the aperture (26). High frequency electrical voltage applied at the feed point (30) achieves launch of an electromagnetic wave from the aperture (26). An alternative feed network uses a 180.degree. hybrid (60) providing simultaneous horizontal and vertical polarization operation.

Flared notch slot antenna

A notch antenna (10) has a metallic notch element (20) deposited on a dielectric substrate (12), which element has a smooth continuously curved edge located adjacent a substrate edge (18). A metallic ground plane (28) is located adjacent the substrate edge (18) spaced very closely to element 20 at one end and at a gradually increased spacing moving away from the one end. An electromagnetic field transmitting coaxial cable (30) with ferrite beads (44) received over its outer conductor for reducing spurious radiation is located on the opposite side of substrate (12,14). The cable center conductor (34) is connected to a metallic strip (38) that is located on the same side of substrate (12,14) as the coaxial cable and tracks the same path as the notch element (20) on the opposite side of substrate (12). The antenna (10) is fed by electromagnetic energy at the closely spaced region of the element (20) and ground plane (28).

Notch monopole antenna

Resonant, end fire antennae that operate over broad frequency bands with a boosted gain at a preferred frequency, that can be incorporated into arrays, and that have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The transmission line and the conductor each have a quarter wavelength tuning stub connected thereto to boost the gain of the antenna at a predetermined frequency. The conductor and the sheath are terminated either with ground connections or by inductive loads.

Growing community of inventors

Ramona, CA, United States of America

John R Glabe