Abstract: An automatic tuning circuit for matching an antenna to a radio receiver. The automatic tuning circuit includes a tunable non-Foster circuit for coupling the receiver and the antenna; and sensing and feedback circuits for sensing the combined capacitance of the tunable non-Foster circuit and the antenna and for tuning the tunable non-Foster circuit to automatically minimize the combined capacitance of the tunable non-Foster circuit and the antenna.

Abstract: An automatic tuning circuit for matching an antenna to a radio receiver. The automatic tuning circuit includes a tunable non-Foster circuit for coupling the receiver and the antenna; and sensing and feedback circuits for sensing the combined capacitance of the tunable non-Foster circuit and the antenna and for tuning the tunable non-Foster circuit to automatically minimize the combined capacitance of the tunable non-Foster circuit and the antenna.

Abstract: A tunable impedance surface, the tunable surface including a plurality of elements disposed in a two dimensional array; and an arrangement of variable negative reactance circuits for controllably varying negative reactance between at least selected ones of adjacent elements in the aforementioned two dimensional array.

Abstract: A differential circuit topology that produces a tunable floating negative inductance, negative capacitance, negative resistance/conductance, or a combination of the three. These circuits are commonly referred to as “non-Foster circuits.” The disclosed embodiments of the circuits comprises two differential pairs of transistors that are cross-coupled, a load immittance, multiple current sources, two Common-Mode FeedBack (CMFB) networks, at least one tunable (variable) resistance, and two terminals across which the desired immittance is present. The disclosed embodiments of the circuits may be configured as either a Negative Impedance Inverter (NII) or a Negative Impedance Converter (NIC) and as either Open-Circuit-Stable (OCS) and Short-Circuit-Stable (SCS).

Abstract: A vehicle or other host station includes first and second antennas, a fast semiconductor switch, a switching controller, and an RF receiver. The controller toggles the switch at a calibrated switching rate to selectively and alternately connect the first antenna to one of the RF receiver and a load having a calibrated impedance value. The first antenna may be a parasitic element in any embodiment using the load. The semiconductor switch may be a CMOS device or a Gallium Arsenide semiconductor switch. A switching control method for use in a vehicle or other host station having the first antenna, the second antenna, and the RF receiver includes transmitting a switching signal from the controller to the switch, and toggling the switch at a calibrated switching rate in response to the switching signal to selectively and alternately connect the first antenna to one of the RF receiver and the load.

Abstract: An apparatus and method for a detector are disclosed. The apparatus disclosed contains an extractor layer, an absorber layer disposed adjacent to the extractor layer, a first electrical contact and a second electrical contact. The absorber layer is configured to absorb photons of incident light and generate minority electrical carriers and majority electrical carriers. In the disclosed apparatus, the top surface of the absorber layer is shaped as a pyramid, the extractor layer is electrically connected with the absorber layer and with the first electrical contact for extracting the minority electrical carriers, and the absorber layer is electrically connected with the extractor layer and with the second electrical contact to extract the majority electrical carriers.

Abstract: A method and system for determining an optimized artificial impedance surface is disclosed. An artificial impedance pattern is calculated on an impedance surface using an optical holographic technique given an assumed surface wave profile and a desired far field radiation pattern. Then, an actual surface wave profile produced on the impedance surface from the artificial impedance pattern, and an actual far field radiation pattern produced by the actual surface wave profile are calculated. An optimized artificial impedance pattern is then calculated by iteratively re-calculating the artificial impedance pattern from the actual surface wave profile and the desired far field radiation pattern. An artificial impedance surface is determined by mapping the optimized artificial impedance pattern onto a representation of a physical surface.

Abstract: A method for designing artificial impedance surfaces is disclosed. The method involves matching impedance component values required for a given far-field radiation pattern (determined, for example, by holographic means) with measured or simulated impedance component values for the units of a lattice of conductive structures used to create an artificial impedance surface, where the units of the lattice have varied geometry. For example, a unit could be a square conductive structure with a slice (removed or missing material) through it. The measured or simulated impedance components are determined by measuring wavevector values for test surfaces in three or more directions over any number of test surfaces, where each unit of a given test surface has the same geometric shape and proportions as all of the other units of that test surface, but each test surface has some form of variation in the unit geometry from the other test surfaces. These test measurements create a table of geometry vs.

Abstract: A reflectarray is disclosed. The reflectarray includes a first array of conductive patches supported by a substrate, wherein each conductive patch in the first array has a first center line along a Y-direction and a second centerline along an X-direction, a plurality of first variable capacitors, wherein each first variable capacitor is electrically coupled to one of the conductive patches in the first array along the first centerline, and a plurality of second variable capacitors, wherein each second variable capacitor is electrically coupled to one of the conductive patches in the first array along the second centerline.

Abstract: A low cost radar system that employs monopulse beamforming to detect objects in the road-way both in elevation and azimuth. In one non-limiting embodiment, a beamforming receiver architecture includes a first beamforming device and a plurality of antennas coupled to the first beamforming device, and a second beamforming device and a plurality of antennas coupled to the second beamforming device. The first and second beamforming devices are oriented 90° relative to each other so that the receive beams provided by the first beamforming device detect objects in azimuth and the receive beams provided by the second beamforming device detect objects in elevation. A first switch is provided to selectively couple the sum pattern signal from the first and second beamforming devices to one output line, and a second switch is provided to selectively couple the difference pattern signals from the first and second beamforming devices to another output line.

Abstract: A method of and apparatus for modulating an optical carrier by an incident electromagnetic field. The electromagnetic field propagates in a dielectric-filled transverse electromagnetic waveguide, At least one slice of an electro-optic material is disposed in the dielectric-filled transverse electromagnetic waveguide, the electro-optic material in the dielectric-filled transverse electromagnetic waveguide having at least one optical waveguide therein which has at least a major portion thereof guiding light in a direction orthogonal with respect to a direction in which the dielectric-filled transverse electromagnetic waveguide guides the incident electromagnetic field. Light is caused to propagate in the at least one optical waveguide in the at least one slice of an electro-optic material in the dielectric-filled transverse electromagnetic waveguide for modulation by the incident electromagnetic field.

Abstract: An artificial impedance structure and a method for manufacturing same. The structure contains a dielectric layer having generally opposed first and second surfaces, a conductive layer disposed on the first surface, and a plurality of conductive structures disposed on the second surface to provide a preselected impedance profile along the second surface.

Abstract: A dual frequency radar antenna for connection to a first radar transmitter/receiver set which operates in a relatively lower frequency band and to a second radar transmitter/receiver set which operates in a relatively higher frequency band. The dual frequency radar antenna has a spherical dielectric lens having a first array of inputs coupled with the first radar transmitter/receiver set and a second array of inputs coupled with the second radar transmitter/receiver set. The spherical dielectric lens forms relatively higher frequency beams that are relatively tightly spaced about a centerline of the spherical dielectric lens while the spherical dielectric lens also forms relatively lower frequency beams that are relatively farther spaced about a centerline of the spherical dielectric lens than are the relatively higher frequency beams.

Abstract: A collision avoidance system for reducing false alerts by estimating the elevation of a target, includes short and long range single-dimensional scanning radar sensors having differing ranges and beam angles of inclination, and a digital fusion processor, and preferably includes a locator device, an inclinometer, and a memory storage device cooperatively configured to further perform trend analysis, and target tracking.

Abstract: One or more of the embodiments of a dual band stacked patch antenna described herein employ an integrated arrangement of a global positioning system (GPS) antenna and a satellite digital audio radio service (SDARS) antenna. The dual band antenna receives right hand circularly polarized GPS signals in a first frequency band, left hand circularly polarized SDARS signals in a second frequency band, and vertical linear polarized SDARS signals in the second band. The dual band antenna includes a ground plane element, an upper radiating element (which is primarily utilized to receive SDARS signals), dielectric material between the ground plane element and the upper radiating element, and a lower radiating element (which is primarily utilized to receive GPS signals) surrounded by the dielectric material. The dual band antenna uses only one conductive signal feed to receive both GPS and SDARS signals.

Abstract: A low cost radar system that employs monopulse beamforming to detect objects in the road-way both in elevation and azimuth. In one non-limiting embodiment, a beamforming receiver architecture includes a first beamforming device and a plurality of antennas coupled to the first beamforming device, and a second beamforming device and a plurality of antennas coupled to the second beamforming device. The first and second beamforming devices are oriented 90° relative to each other so that the receive beams provided by the first beamforming device detect objects in azimuth and the receive beams provided by the second beamforming device detect objects in elevation. A first switch is provided to selectively couple the sum pattern signal from the first and second beamforming devices to one output line, and a second switch is provided to selectively couple the difference pattern signals from the first and second beamforming devices to another output line.

Abstract: A collision avoidance system for reducing false alerts by estimating the elevation of a target, includes short and long range single-dimensional scanning radar sensors having differing ranges and beam angles of inclination, and a digital fusion processor, and preferably includes a locator device, an inclinometer, and a memory storage device cooperatively configured to further perform trend analysis, and target tracking.

Abstract: An integrated multi-beam antenna with a shared dielectric lens is disclosed. The antenna is formed by positioning the feed apertures of a plurality of waveguide feeds at positions located on the surface of the shared dielectric lens. The angular direction and shape of radiation beams produced by the waveguide feeds are determined by the physical and dielectric characteristics of the lens, the location of feed apertures of the waveguide feeds on the surface of the lens, and the frequency of electromagnetic energy propagating in the waveguide feeds. The principles of the invention are applied to realize an inexpensive, integrated multi-feed antenna adapted to provide desired angular areas of coverage for both a long range and short range radar in an automotive radar safety system.

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: An integrated multi-beam antenna with a shared dielectric lens is disclosed. The antenna is formed by positioning the feed apertures of a plurality of waveguide feeds at positions located on the surface of the shared dielectric lens. The angular direction and shape of radiation beams produced by the waveguide feeds are determined by the physical and dielectric characteristics of the lens, the location of feed apertures of the waveguide feeds on the surface of the lens, and the frequency of electromagnetic energy propagating in the waveguide feeds. The principles of the invention are applied to realize an inexpensive, integrated multi-feed antenna adapted to provide desired angular areas of coverage for both a long range and short range radar in an automotive radar safety system.