Abstract: An imager comprising a sphere of dielectric material and a geodesically configured substrate disposed adjacent said sphere. The geodesically configured substrate comprises a plurality of triangularly shaped elements, at least selected ones of the triangularly shaped elements having an array of detectors disposed thereon, the detectors in the array also being disposed adjacent the dielectric sphere for receiving and detecting incoming electromagnetic waves delivered via said sphere.

Abstract: An apparatus and methods for operating a frequency selective surface are disclosed. The apparatus can be tuned to an on/off state or transmit/reflect electromagnetic energy in any frequency. The methods disclosed teach how to tune the frequency selective surface to an on/off state or transmit/reflect electromagnetic energy in any frequency.

Abstract: A tunable impedance surface includes a varactor. The varactor comprises a bottom electrode formed on a surface of a substrate. First and second ferroelectric elements are on top of the bottom electrode and electrically connected to one another through the bottom electrode. A first top electrode is on top of and electrically connected to the first ferroelectric element and a second top electrode is on top of and electrically connected to the second ferroelectric element.

Abstract: A tunable impedance surface capable of steering a multiband radio frequency beam in two different, independently band-wise controllable directions. The tunable surface has a ground plane and a plurality of first conductive elements disposed in a first array a first distance therefrom, the first distance being less than a wavelength of a lower frequency band of the multiband radio frequency beam. A first capacitor arrangement controllably varies capacitance between selected ones of the first conductive elements. A plurality of second conductive elements are disposed in a second array a second distance from the plurality of first conductive elements, the second distance being less than a wavelength of a higher frequency band of the multiband radio frequency beam, the plurality of first conductive elements serving as a ground plane for the plurality of second conductive elements. A second capacitor arrangement controllably varies capacitance between selected ones of the second conductive elements.

Abstract: The radiation properties and wave guiding properties of frequency selective surfaces are used in conjunction with closely spaced antenna elements to fabricate antenna structures having adjustable radiation characteristics. The direction, magnitude, and polarization of radiation patterns for such antenna structures can be adjusted by varying the texture or patterning of layers of conducting material forming the frequency selective surfaces. The invention enables the fabrication of low profile antenna structures that can easily be conformed or integrated into complex surfaces without sacrificing antenna performance.

Abstract: An apparatus and methods for operating a frequency selective surface are disclosed. The apparatus can be tuned to an on/off state or transmit/reflect electromagnetic energy in any frequency. The methods disclosed teach how to tune the frequency selective surface to an on/off state or transmit/reflect electromagnetic energy in any frequency.

Abstract: A chaff element for interfering with radar signals. The chaff element has a dielectric substrate and a pair of elongate electrically conductive elements, having a total length of approximately one-half wavelength of the radar signals or otherwise tuned to the radar signals, disposed on the dielectric substrate. A switch is arranged to electrically couple the pair of elongate elements together in response to a control signal generated by an oscillator circuit and a battery. The chaff element can be used in a method of providing a countermeasure against radar signals. A plurality of chaff elements can be deployed in an airspace above a radar unit emitting a radar signal and interfere with the radar signal by opening and closing the switches of the chaff elements while deployed in said airspace above the radar unit.

Abstract: A control system and method for controlling switching between and among multiple antennas in a diversity antenna system comprising a radio head unit associated with a radio receiver; two or more antennas, either located in separate antenna modules or co-located in the same antenna module; a switch circuit; and a single cable. Control signals for controlling switching are provided as changes in a DC power supply signal carried on the single cable. In the case of multiple antenna modules, the radio head unit and the antenna modules are connected by the single cable using a daisy-chain architecture.

Abstract: A chaff element for interfering with radar signals. The chaff element has a dielectric substrate and a pair of elongate electrically conductive elements, having a total length of approximately one-half wavelength of the radar signals or otherwise tuned to the radar signals, disposed on the dielectric substrate. A switch is arranged to electrically couple the pair of elongate elements together in response to a control signal generated by an oscillator circuit and a battery. The chaff element can be used in a method of providing a countermeasure against radar signals. A plurality of chaff elements can be deployed in an airspace above a radar unit emitting a radar signal and interfere with the radar signal by opening and closing the switches of the chaff elements while deployed in said airspace above the radar unit.

Abstract: The radiation properties and wave guiding properties of frequency selective surfaces are used in conjunction with closely spaced antenna elements to fabricate antenna structures having adjustable radiation characteristics. The direction, magnitude, and polarization of radiation patterns for such antenna structures can be adjusted by varying the texture or patterning of layers of conducting material forming the frequency selective surfaces. The invention enables the fabrication of low profile antenna structures that can easily be conformed or integrated into complex surfaces without sacrificing antenna performance.

Abstract: A radiating coaxial cable transmission line that may be used as an antenna. Mechanisms are incorporated for boosting the rate of conversion of bifilar mode to monofilar mode.

Abstract: A rectenna structure comprising a flexible, dielectric sheet of material; a plurality of metallic lenslets disposed on the sheet of material; and a plurality of diodes disposed on the sheet of material, each diode in said plurality of diodes being arranged at a focus of a corresponding one of said plurality of metallic lenslets.

Abstract: A digitally controlled tunable impedance surface. The tunable impedance surface is of the type having a two dimensional array of conducting plates disposed adjacent a dielectric medium; a ground plane spaced from the two dimensional array of conducting plates, the dielectric medium occurring at least between and separating the two dimensional array of conducting plates and the ground plane; and conductors coupling alternating ones of the conducting plates to the ground plane. A plurality of voltage controlled capacitors are coupled between adjacent plates in the two dimensional array of conducting plates and an array of digital to analog converters are disposed preferably on or near the ground plane. Each digital to analog converter has analog output voltage pads coupled to selected ones of adjacent conducting plates and has at least a digital input for receiving digital words representing at least in part analog voltages to be applied to the selected ones of the adjacent conducting plates.

Abstract: The radiation properties and wave guiding properties of frequency selective surfaces are used in conjunction with closely spaced antenna elements to fabricate antenna structures having adjustable radiation characteristics. The direction, magnitude, and polarization of radiation patterns for such antenna structures can be adjusted by varying the texture or patterning of layers of conducting material forming the frequency selective surfaces. The invention enables the fabrication of low profile antenna structures that can easily be conformed or integrated into complex surfaces without sacrificing antenna performance.

Abstract: A method for improving the efficiency of antennas having transparent thin-film conductive surfaces, and antennas improved by the method are disclosed. For a selected frequency of antenna operation, values for surface current density in areas distributed over the surface of the thin-film are determined. Regions of the surface containing areas having concentrated current flow are identified based upon the determined values of current density. Antenna efficiency is improved by increasing conductivity in areas of the thin-film surface found to have concentrated current flow. The method enables the improvement of the efficiency of antennas having transparent thin-film conducting surfaces, without unnecessarily obstructing the optical view through the thin-film surfaces of the antennas.

Abstract: In one embodiment, a high frequency quasi optical oscillator power source is provided which includes an array of amplifier devices each having an input antenna tuned for a fundamental frequency. A amplifier coupled to the input antenna amplifies fundamental frequency signals. A multiplier coupled to the amplifier provides signals at a multiple of the fundamental frequency and at the fundamental frequency. The output antenna coupled to the multiplier is tuned at the fundamental frequency and at a multiple of the fundamental frequency. A grating lobe-to-main lobe converter located above the array of amplifier devices converts grating lobe power to main lobe power at the multiple of the fundamental frequency. A frequency selective reflector opposes the amplifier array to reflect signals at the fundamental frequency and to pass signals at the multiple of the fundamental frequency.

Abstract: A chaff element for interfering with radar signals. The chaff element has a dielectric substrate and a pair of elongate electrically conductive elements, having a total length of approximately one-half wavelength of the radar signals or otherwise tuned to the radar signals, disposed on the dielectric substrate. A switch is arranged to electrically couple the pair of elongate elements together in response to a control signal generated by an oscillator circuit and a battery. The chaff element can be used in a method of providing a countermeasure against radar signals. A plurality of chaff elements can be deployed in an airspace above a radar unit emitting a radar signal and interfere with the radar signal by opening and closing the switches of the chaff elements while deployed in said airspace above the radar unit.

Abstract: Disclosed is an antenna system including a Luneberg Lens having a spherically shaped outer surface and a spherically shaped focal surface spaced from its outer surface with a plurality of patch antenna elements disposed along the focal surface of the Luneberg Lens; and a power combiner for combining signals received by said plurality of patch antenna elements. The disclosed antenna system may be used a part of a robust GPS system having a plurality of GPS satellites each transmitting a GPS signal; a plurality of airborne GPS platforms, each GPS platform including a GPS transmitter for transmitting its own GPS signal, the GPS signals being transmitted from the plurality of airborne GPS platforms being differentiated from the GPS signals transmitted by visible GPS satellites; and at least one terrestrially located GPS receiver for receiving the GPS signals transmitted by visible ones of the GPS satellites and by visible ones of said airborne GPS platforms.

Abstract: An adaptive surface has a dielectric surface with a repeating pattern of electrically conductive structures disposed thereon or therein, the dielectric surface in combination with repeating pattern of electrically conductive structures forming a metasurface for binding surface waves thereto. A plurality of actuators on the dielectric surface alter the shape of the metasurface in response to control signals. A plurality of sensors on the dielectric surface for measuring a desired parameter and converting it to data. A plurality of rectennae disposed on the dielectric surface for providing electrical power to said actuators and to said sensors. A plurality of data antennas are disposed on or in the dielectric surface, the data antennas being coupled with data receivers and data transmitters for receiving data from an external source for controlling the actuators and for transmitting data from said sensors to an external receiver.

Abstract: A diesel particulate filter including a microwave-absorbing target housed within a waveguide cavity lined along the walls with a hard-electromagnetic surface (HES). The HES modifies specific electromagnetic boundary conditions for a given design frequency so as to enable the establishment of electromagnetic field patterns which are more uniform across the cavity thereby causing the target material to undergo enhanced uniformity heating. The heating of the microwave absorbing media causes particulate buildup to be vaporized and removed from the filter by the exhaust stream flow.