Abstract: An electronically controlled monolithic array antenna includes a transmission line through which an electromagnetic signal may be propagated, and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element. The antenna element includes a conductive ground plate; an array of conductive edge elements defining the coupling edge, each of the edge elements being electrically connected to a control signal source, and each of the edge elements being electrically isolated from the ground plate by an insulative isolation gap; and a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate across the insulative isolation gap so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.

Abstract: An electronically controlled monolithic array antenna includes a transmission line through which an electromagnetic signal may be propagated, and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element. The antenna element includes a conductive ground plate; an array of conductive edge elements defining the coupling edge, each of the edge elements being electrically connected to a control signal source, and each of the edge elements being electrically isolated from the ground plate by an insulative isolation gap; and a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate across the insulative isolation gap so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.

Abstract: A scanning antenna with an antenna element having an evanescent coupling portion includes a waveguide assembly including a transmission line, adjacent the coupling portion, through which an electromagnetic signal is transmitted, permitting evanescent coupling of the signal between the transmission line and the antenna element. First and second conductive waveguide plates, on opposite sides of the transmission line, define planes that are substantially parallel to the axis of the transmission line, each plate extending distally from a proximal end adjacent the antenna element, whereby the propagated signal forms a beam that is confined to the space between the plates and thus limited to a plane that is parallel to the planes defined by the plates. The signal coupled between the transmission line and the antenna element is preferably polarized so that its electric field component is in a plane parallel to the planes defined by the plates.

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 devices 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: An electronically controlled monolithic array antenna includes a transmission line through which an electromagnetic signal may be propagated, and a metal antenna element defining an evanescent coupling edge located so as to permit evanescent coupling of the signal between the transmission line and the antenna element. The antenna element includes a conductive ground plate; an array of conductive edge elements defining the coupling edge, each of the edge elements being electrically connected to a control signal source, and each of the edge elements being electrically isolated from the ground plate by an insulative isolation gap; and a plurality of switches, each of which is selectively operable in response to the control signal to electrically connect selected edge elements to the ground plate across the insulative isolation gap so as to provide a selectively variable electromagnetic coupling geometry of the coupling edge.

Abstract: A microwave switch array includes a plurality of microwave slotlines, each of which is controlled by a semiconductor switch including a first PIN junction formed by a primary P-type electrode and a primary N-type electrode separated by the slotline. The switches inject a plasma into the slotline in response to a potential applied across the first PIN junction. Each of the switches includes a second PIN junction between the primary P-type electrode and a secondary N-type electrode, and a third PIN junction between the primary N-type electrode and a secondary P-type electrode. Metal contacts connect the primary P-type electrode and the secondary N-type electrode across second PIN junction, and the primary N-type electrode and the secondary P-type electrode across the third PIN junction. The secondary electrodes extract plasma that diffuses away from the first PIN junction, thereby minimizing the performance degrading effects of plasma diffusion.

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 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: 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: 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: 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: A scanning antenna is disclosed including: a rotatable cylinder having an outer surface; a continuously, or steppingly, varying period conductive grating pattern of separated strips on the outer surface, the varying conductive grating pattern of separated strips defining a grating axis; and a first elongated dielectric waveguide defining a first waveguide axis, the first elongated dielectric waveguide being located proximally adjacent and alongside the varying conductive grating pattern of separated strips so as to evanescently couple electromagnetic signals with the first elongated dielectric waveguide. The scanning antenna provides advantages in that the gain is high.

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.