Abstract: A beam-forming antenna for transmission and/or reception of an electromagnetic signal having a given wavelength in a surrounding medium includes a transmission line electromagnetically coupled to an array of individually controllable antenna elements, each of which is oscillated by the signal with a controllable amplitude. The antenna elements are arranged in a linear array and are spaced from each other by a distance that does not exceed one-third the signal's wavelength in the surrounding medium. The oscillation amplitude of each of the individual antenna elements is controlled by an amplitude controlling device, such as a switch, a gain-controlled amplifier, or a gain-controlled attenuator. The amplitude controlling devices, in turn, are controlled by a computer that receives as its input the desired beamshape, and that is programmed to operate the amplitude controlling devices in accordance with a set of stored amplitude values derived empirically for a set of desired beamshapes.

Abstract: A reconfigurable directional antenna for transmission and reception of electromagnetic radiation includes a transmission line aligned with and adjacent to a metal antenna element with an evanescent coupling edge having a selectively variable electromagnetic coupling geometry. The shape and direction of the beam are determined by the selected coupling geometry of the coupling edge, as determined by the pattern of electrical connections selected for physical edge features of the coupling edge. The electrical connections between the edge features are selected by the selective actuation of an array of “on-off” switches that close and open electrical connections between individual edge features. The selection of the “on” or “off” state of the individual switches thus changes the electromagnetic geometry of the coupling edge, and, therefore the direction and shape of the transmitted or received beam. The actuation of the switches may be accomplished under the control of an appropriately-programmed computer.

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: The addition of semiconductor spacers into the spaces between the metal strips of a metal grid permits electron-hole plasmas to be introduced there controllably. Thus, the grid can be made to transmit or reflect an incident wave with a polarization perpendicular to the strips depending on whether or not the spacers are filled with minority carriers. The presence of carriers may be controlled electrically, optically and by field effect means which permit the basic metal strip/semiconductor structure (MGSS) to operate as a reconfigurable hologram, a reflector, a phase shifter, a switch, and a beam-steering antenna.

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: Systems and methods for scanning antennas with plasma gratings are described. An apparatus includes a semiconductor slab and an electrode set or illuminating system to inject a plasma grating. The systems and methods provide advantages in the compactness and higher efficiency in comparison with existing antennas.

Abstract: Systems and methods for thermal imagining are described. An apparatus includes a rotatable radial scanning antenna. The systems and methods provide advantages in that fires can be detected, and their positions determined, over substantial distances and through obscurants such as smoke and/or rain.

Abstract: Systems and methods for two dimensional millimeter wave imaging are described. A system includes a spindle assembly defining a rotation axis; a waveguide assembly connected to the spindle assembly, the waveguide assembly including a first dielectric waveguide defining a first axis; and a grating assembly connected to the spindle assembly, the grating assembly including a plurality of sectors, each of the plurality of sectors including a varying period conductive grating pattern. A varying period of the varying period conductive grating pattern is a function of an angle defined by a rotational position of the grating assembly with regard to the rotation axis. The systems and methods provide advantages in that an image can be scanned quickly using an inexpensive system.

Abstract: Systems and methods for guided wave antennas are described. Apparatus is disclosed comprising: a dielectric nonphotoconductive waveguide defining a principle axis; a grating carrier connected to the dielectric nonphotoconductive waveguide, the grating carrier i) including a photoconductive material and ii) defining a photoconductive axis that is substantially parallel to the principle axis; a spatial light modulator optically connected to the layer of photoconductive material; and a source of illumination optically connected to the spatial light modulator and the layer of photoconductive material.

Abstract: Systems and methods for optical control of radar antenna beam steering are described. An apparatus includes: a feeder waveguide; and a waveguide array electromagnetically coupled to said feeder waveguide, said waveguide array including: a plurality arms, each of said plurality of arms including: a plasma induced modulator having a transmission coefficient that is .ltoreq.1, said plasma induced modulator including: a rib waveguide electromagnetically coupled to said feeder waveguide. The systems and methods provide advatages in that optical beam steering is achieved with a lightweight inexpensive apparatus.

Abstract: Systems and methods for optically controlled phase shifters are described.