Abstract: A method for making an antenna and the antenna itself are described. The antenna comprises a first region having a first refractive index and a second region having a negative refractive index, the second region substantially surrounding the first region, such that radiation outside the second region is reproduced in the first region.

Abstract: A reflector antenna system may include at least one antenna reflector having an arcuate shape and defining an antenna beam, a feed device spaced apart from the at least one antenna reflector, and a phased array antenna positioned in the antenna beam between the at least one antenna reflector and the feed device. More particularly, the phased array antenna may include a substrate and a plurality of back-to-back pairs of first antenna elements carried by the substrate and configured for defining at least one feed-through zone for the antenna beam. The phased array antenna may further include a plurality of back-to-back pairs of second antenna elements carried by the substrate and defining at least one active beamsteering zone for the antenna beam.

Abstract: A reflector antenna system may include at least one antenna reflector having an arcuate shape and defining an antenna beam, and a phased array antenna positioned in the antenna beam. More particularly, the phased array antenna may include a substrate and a plurality of back-to-back pairs of first antenna elements carried by the substrate and configured for defining at least one feed-through zone for the antenna beam. Moreover, the phased array antenna may further include a plurality of second antenna elements carried by the substrate and defining at least one active zone for the antenna beam.

Abstract: An antenna unit formed in the shape of a hollow box comprising (a) a substrate forming the front side of the antenna unit, (b) a first microstrip antenna array formed on the substrate, (c) a second microstrip antenna array formed on the substrate, (d) a ground plane forming the rear side of the antenna unit, and (e) a plurality of periodic filters formed on the ground plane. The periodic filters are formed by etching a series of circular patterns, or holes, through the ground plane. The periodic stop band filters provide for improved isolation between the microstrip antenna arrays, without the need for adding additional costly or space consuming components.

Abstract: A low profile, wide band gap antenna having a high impedance surface, the high impedance surface including a conductive plane and an array of conductive elements spaced from the conductive plane by a distance which is no greater than 10% of a wavelength of an operating frequency of the antenna structure. The conductive plane has an opening therein which is driven by an antenna driving element adjacent the opening in the conductive plane.

Abstract: A high-frequency imaging system for the millimeter and submillimeter radiation includes a high frequency lens to image an object at its focal plane. The object emits electromagnetic radiation at a first frequency above the microwave band of the electromagnetic spectrum. A local oscillator generates an electromagnetic beam at a second frequency to illuminate a plurality of dual-frequency antennas at the focal plane of the lens. Intermodulation of first and second frequencies generates a signal distribution of a third frequency over the focal plane, which represents an image. Also, a method of providing an image at the third frequency of an object emitting electromagnetic radiation at a first frequency is provided. The method includes imaging the electromagnetic radiation at the first frequency from each point of the object onto the focal plane. An electromagnetic beam is transmitted to illuminate all elements of the focal plane array.

Abstract: An electromagnetic bandgap material is electrically attached to an edge, and enables high isolation between antennas due to the attenuation of surface waves. The disclosed embodiments further provide narrow reactive edge treatments in the form of artificial magnetic conductors (AMCs) whose physical width is less than 1/10 of a free space wavelength for the frequency of surface currents intended to be suppressed. These embodiments still further provide several AMCs suitable for this purpose, along with several exemplary manufacturing techniques for the AMCs.

Abstract: A phased array antenna (100) having a frequency selective surface comprises a substrate (125) and an array of antenna elements (140) thereon. Each antenna element comprises a medial feed portion (42) and a pair of legs (49) extending outwardly therefrom. Adjacent legs of adjacent antenna elements include respective spaced apart end portions (51). The antenna further comprises at least one fluidic dielectric residing within at least one cavity (170) within the substrate and arranged between a plane where the array of dipole antenna elements reside and a ground plane (150), at least one composition processor (104) adapted for dynamically changing a composition of said fluidic dielectric, and a controller (102) for controlling the composition processor to selectively vary at least one of a permittivity and a permeability of the fluidic dielectric in at least one cavity in response to a control signal (105).

Abstract: A multisource antenna includes at least two excitation sources and for spatially channeling energy picked up/radiated by the excitation sources and providing for frequency decoupling between the bands respectively corresponding to the waves received/transmitted by the sources. The sources are arranged on a ground plane to interleave radiating apertures at the level of the spatial and frequency selective arrangements.

Abstract: A multi layered high impedance structure presents a high impedance to multiple frequency signals, with a different frequency for each layer. Each layer comprises a dielectric substrate, and an array of radiating elements such as parallel conductive strips or conductive patches on the substrate's top surface, with a conductive layer on the bottom surface of the bottommost layer. The radiating elements of succeeding layers are vertically aligned with conductive vias extending through the substrates to connect the radiating elements to the ground plane. Each layer presents as a series of parallel resonant L-C circuits to an E field at a particular signal frequency, resulting in a high impedance surface at that frequency. The new structure can be used as the substrate for a microstrip patch antenna to provide an optimal electrical distance between the resonator and backplane at multiple frequencies.

Abstract: A component that is reflective for broadcast-frequency energy includes a nonmetallic substrate having a substrate surface, and a layered coating overlying and contacting the substrate. The layered coating has an electrically conductive layer overlying and contacting the substrate surface, and a layer of a white paint overlying and contacting the electrically conductive layer. The white paint is formed of a plurality of particles including a plurality of pigment particles. Each pigment particle has a composition of A[xAl(1?x)Ga]2O4(?D), A is selected from the group consisting of zinc, cadmium, and magnesium, D is a dopant selected from the group consisting of a cationic dopant having an ionic valence greater than +2 and an anionic dopant, the value of x is from 0 to 1, and the value of ? is from 0 to about 0.2. The paint further includes an inorganic or an organic binder mixed with the particles to form a mixture.

Abstract: A low profile antenna system includes an artificial magnetic conductor comprising a frequency selective surface (FSS) having an effective sheet capacitance which is electronically variable to control resonant frequency of the AMC and the resonant frequency of an antenna element positioned adjacent to the FSS.

Abstract: Disclosed herein is an antenna that is integrally encompassed within a three-dimensional shaped substance that has a permittivity or permeability constant greater than one. Such an encompassed antenna results in the production of radiated energy at a particular frequency and gain that can conventionally only be produced by a larger antenna.

Abstract: Dielectric lenses (6) with an outer dimension of about 0.5 to 1.5 times a wavelength are arranged on front faces of respective slots (3) of a waveguide slot array antenna (1). The dielectric lenses (6) are formed in a panel structure where they have been connected integrally through a dielectric panel (7) so that they cover a front face of the antenna. Spherical waves radiated from the slots are converted into a flat wave by the dielectric lenses, and a composite wave of radiation waves from the respective slots becomes a flat wave which hardly includes ripples, so that an antenna gain is remarkably improved as compared with a case that dielectric lenses are not provided.

Abstract: A substrate (300) for an RF device includes a plurality of layers (102) of dielectric material cofired in a stack. The plurality of layers (102) is formed from a material having a permittivity. Selected ones of the layers (102) have a pattern of perforations (106) formed in at least one perforated area (104). The perforated areas (104) are generally aligned with one another in the stack to lower one or more of an effective value of a permittivity and a loss tangent in a least one spatially defined region (504) of the substrate (300).

Abstract: A method of forming a periodic index of refraction pattern in a superlattice of a solid material to achieve photonic bandgap effects at desired optical wavelengths is disclosed. A plurality of space group symmetries, including a plurality of empty-spaced buried patterns, are formed by drilling holes in the solid material and annealing the solid material to form empty-spaced patterns of various geometries. The empty-spaced patterns may have various sizes and may be formed at different periodicities, so that various photonic band structures can be produced for wavelength regions of interest.

Abstract: A feed structure (105) for a horn antenna (100). The feed structure can include a first waveguide (110) and a second waveguide (115) having a first portion at least partially disposed within the first waveguide. The second waveguide also can include a second portion intersecting a first wall (240) of the first waveguide. The first wall can include a first frequency selective surface (244) at an intersection (280) of the first wall and the second portion of the second waveguide. The first waveguide can be operatively coupled to a first horn section (130) and the second portion can be operatively coupled to a second horn section (135).

Abstract: An apparatus and method to twist the field polarization of an electromagnetic wave over a desired frequency band is described. In one embodiment, a transmission twister rotates the polarization of a linearly-polarized incident field to produce a transmitted field. In one embodiment, the transmission twister includes a resonant polarization-twisting array between two linearly-polarized arrays. In one embodiment, the transmission twister rotates the polarization by 90 degrees. In one embodiment, the transmission twister produces low reflection of a desired incident polarization. In one embodiment, the transmission twister has a transmission coefficient (with respect to the desired incident field polarization and a correspondingly rotated transmitted field polarization) close to unity.

Abstract: An antenna system includes a ground plane and/or antenna elements forming an antenna array. A spatial filtering surface is positioned adjacent the antenna array through which electromagnetic radiation to or from the antenna array passes. The spatial filtering surface includes a dielectric substrate and a plurality of spaced, geometric configured, resonant elements printed on the dielectric substrate and configured and spaced from each other to have a resonant frequency to filter an electromagnetic field at a selected frequency with respect to an angle of incidence to the dielectric substrate. A dielectric filler is positioned between, above and below each resonant element printed on the dielectric substrate. A spatial filter taper transform is imparted when electromagnetic radiation passes therethrough. A standing wave is created between the ground plane and spatial filtering surface.

Abstract: An electronically reconfigurable artificial magnetic conductor (RAMC) includes a frequency selective surface (FSS) having an effective sheet capacitance which is variable to control resonant frequency of the RAMC. In one embodiment, the RAMC further includes a conductive backplane structure and a spacer layer separating the conductive backplane structure and the FSS. The spacer layer includes conductive vias extending between the conductive backplane structure and the FSS, and voltage variable capacitive circuit elements coupled with the FSS and responsive to bias voltages applied on one or more bias signal lines routed through the conductive backplane structure and the conductive vias.

Abstract: Ad device substantially transparent to electromagnetic radiation of a certain frequency band is presented. The device comprises at least one dielectric structure of a predetermined thickness defined by the central frequency of the operational frequency band of the device, and comprises a predetermined substantially periodic inner pattern inside the dielectric structure composed of a two-dimensional array of substantially identical sub-resonant capacitive elements made of an electrically conducting material and capable of scattering said electromagnetic radiation arranged in a disconnected from each other spaced-apart relationship.

Abstract: An electrically conductive coating of an automotive heatable windshield has a communication window having an enhanced frequency selective surface having arranged passing areas (uncoated areas) and blocking areas (coated areas) to pass and block, respectively, predetermined wavelengths of the electromagnetic spectrum. In one nonlimiting embodiment, the frequency selective surface includes a pattern having a first plurality of arcuate break lines on one side of a dividing break line and a second plurality of arcuate break lines on the other side of the dividing break line. An elongated continuous blocking area is between adjacent break lines. The arcuate break lines of a group are nested within one another with the arcuate break line having the largest radius of curvature adjacent the dividing break line. The break lines each have alternating blocking and passing areas.

Abstract: A spatial filtering surface includes a dielectric substrate and a plurality of spaced, geometrically configured, resonant elements positioned on the dielectric substrate. The resonant elements form concentric rings that each attenuate any electromagnetic radiation passing therethrough a different amount wherein a spatial filter transform is imparted for tapering the magnitude and phase of a produced aperture field.

Abstract: A direct current (DC) inductive shorted patch antenna includes a direct current inductive (DCL) frequency selective surface (FSS) forming the radiating element, a ground plane, a feed, and a radio frequency (RF) short to the ground plane positioned between the feed and the radiating element.

Abstract: An optical device having a photonic crystal structure is provided. The photonic crystal structure includes a plurality of rods/holes, a plurality of light input ports, a plurality of light output ports, a light path; and a defect of rod/hole located in the light path. The photonic crystal structure of the optical device can be optimized to adjust the powers of the lights of the output ports, and thus the output powers having identical intensities can also be achieved. When a plurality of lights is launched via the input ports, the powers and the phases of the lights of the output ports can also be optimized.

Abstract: Apparatus for providing a controllable signal delay along a transmission line, which apparatus comprises a transmission line conductor on a dielectric medium comprised wholly or partially or a semiconductor material, and adjacent periodically separated electromagnetically-coupled elements, the coupling between the elements and the transmission line conductor being controllable through photonic and/or electrical injection of electrical carriers into the dielectric medium, whereby the apparatus is such as to enable control of the velocity of electromagnetic propagation along the transmission line and thereby through the apparatus.

Abstract: A system for generating electromagnetic radiation comprising a flux generator for generating a high intensity current and conversion means in the form of a reflex triode or a plasma focus device for converting said current into a high energy radiation beam.

Abstract: An reconfigurable array of variable conductive elements is provided for reflecting, filtering and steering electromagnetic radiation across a wide range of frequencies. The reconfigurable array is combined with a transmitting antenna to make a steerable antenna. The reconfigurable array surrounds the transmitting antenna and reflects all transmissions except on selected radials where apertures in the reconfigurable array are formed for permitting transmission lobes. The reconfigurable arrays can be arranged in stacked layers to make transceiving multiband antennas. Communications networks using the steerable antennas nas and arrays are also disclosed.

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 optically transparent dielectric reflector (200) that reflects an incident millimeter-wave beam at a design frequency. The reflector (200) includes layers of different optically transparent dielectric materials. The thickness of the individual layers is chosen so that the transmitted waves cancel almost completely in the forward direction, yielding a high degree of transmission loss and substantial reflection. In the preferred embodiment, the invention is comprised of alternating layers of optical sapphire and air. In the best mode, there are seven sapphire layers, with outer sapphire layers (50) having a nominal thickness of 70.8 mils, inner sapphire layers (52) with a nominal thickness of 30.4 mils, and air layers have a nominal thickness of 32.0 mils Vented metal spacers (54) are used to maintain optimal thickness of air layers.

Abstract: A photonic crystal having reversibly tunable photonic properties. The photonic crystal includes a phase change material having a plurality of structural states that vary with respect to fractional crystallinity. Optical constants including refractive index, extinction coefficient and permittivity vary as the fractional crystallinity of the phase change material is varied thereby providing tunability of photonic crystal properties. Variations among the structural states of the phase change material are reversibly effected through the addition of energy in forms including optical or electrical energy. The photonic crystals may include defects that provide photonic states within the photonic band gap. The position of these states is tunable through the control of the fractional crystallinity of the phase change material included in the photonic crystal. Electromagnetic radiation resonators including photonic crystals having photonic states in the photonic band gap are further provided.

Abstract: An antenna system for receiving electromagnetic waves of predetermined frequency range is disclosed comprising an antenna configured for receiving electromagnetic waves; and a plasma filter configured for reflecting a first electromagnetic frequency emitted from a remote source, while at the same time passing a second electromagnetic frequency, such that one of the first electromagnetic frequency and the second electromagnetic frequency is received by the antenna. The electromagnetic wave filter can comprise a power medium positioned with respect to a region of space; a composition disposed within the region of space for forming a plasma; an energy source electromagnetically coupled to the power medium such that a plasma may be formed in the region of space; and a control mechanism for varying plasma density within the region of space, wherein the plasma density will reflect a first electromagnetic frequency emitted from a remote source, while at the same time passing a second electromagnetic frequency.

Abstract: A reconfigurable frequency selective surface (FSS) includes a plurality of conducting patches supported on the surface of a dielectric layer, with selectable electrical interconnections between the conducting patches so as to provide a desired characteristic. The reconfigurable FSS can be used in a reconfigurable artificial magnetic conductor (AMC). A reconfigurable AMC includes a dielectric layer, a conducting back-plane on one surface of the dielectric layer, and a reconfigurable FSS on the other surface of the dielectric layer. A reconfigurable AMC can be used as a dynamically reconfigurable ground plane for a low-profile antenna system.

Abstract: A small, lightweight radio wave lens antenna device is proposed in which freedom of selection of the installation place is high, which can be compactly installed e.g. on a wall surface, and in which restriction of installation space is relaxed. A hemispherical Luneberg lens 2 is mounted on a reflecting plate 1, antenna elements 4 are supported by a retainer 3, they are integrally combined, and a mounting portion 5 is provided for mounting the reflecting plate 1 to a installation portion such as a wall surface with the reflecting plate 1 substantially vertical. The reflecting plate 1 may have such a shape that an area other than the area for reflecting radio waves from directions in a predetermined range is removed, preferably in the shape of a fan. The hemispherical Luneberg lens 2 is mounted on the reflecting plate 1, offset toward the small arcuate edge 1b of the fan.

Abstract: This invention relates to a low-profile lens antenna. In particular, this invention relates to a low-profile lens antenna for use in a depression in a surface, e.g. a concavity in the ground. A low-profile lens antenna is provided that comprises a feed and a lens, wherein the lens is shaped to produce a radiation pattern that shows a general increase in power from 0° to 90° from the central axis of the antenna when illuminated with radiation from the feed.

Abstract: The present invention provides a dual antenna system where a first antenna element has a metallic surface with openings that are resonant at frequencies other than the operating frequency of a second antenna element. The openings are sized such that the metallic components are relatively transparent at and near resonant frequencies of those openings. According to the present invention, the resonant frequencies of the openings may be the transmitting or receiving frequencies of the second antenna element, or of nearby antennas.

Abstract: An array of dielectric wave antennas is disclosed. Each wave antenna has a central dielectric portion and two dielectric tapered portions, disposed on opposite sides of the central dielectric portion. The array is deployed in a lens shape and allows variation of the phase delay of an incident electromagnetic wave when passing through the array.

Abstract: A radio frequency reconfigurable lens is provided. In particular, a lens comprising at least two opposed frequency selective surface sheets is provided. A relative phase shift may be imparted to an incident radio frequency wave by varying the distance between at least some of the unit cells of a first of the FSS sheets and adjacent unit cells on a second of the FSS sheets. In order to provide a desired phase taper across the width of a lens, and/or to provide different phase shift amounts, pairs of FSS surfaces having controllable columns or rows can be cascaded together. According to an additional aspect of the present invention, radio frequency waves can be scanned by cascading multiple tunable stages. The present invention also provides a radio frequency shutter.

Abstract: Leaky wave antenna beam steering that is capable of steering in a backward direction, as well as further down toward the horizon in the forward direction than was previously possible, and also directly toward zenith. The disclosed antenna and method involve applying a non-uniform impedance function across a tunable impedance surface in order to obtain such leaky wave beam steering.

Abstract: A radio frequency aperture comprising a plurality of insulating layers disposed in a stack, each layer including an array of conductive regions, the conductive regions being spaced from adjacent conductive regions. Also disclosed is method of bending or steering radio frequency waves impinging an antenna. The method includes disposing a plurality of insulating layers arranged in a stack between a source of the radio frequency waves and the antenna, wherein each insulating layer includes an array of conductive regions, the conductive regions being spaced from adjacent conductive regions and forming capacitive elements. The capacitance of the capacitive elements in the plurality of insulating layers is adjusted as a function of their location in the plurality of insulating layers.

Abstract: A multiple slot antenna wherein the slots are arranged in a planar configuration and therein the antenna further comprises a plurality of plano-convex Rotman lenses disposed in a stack, each plano-convex Rotman lens in said stack having a major surface disposed at an angle to the planar configuration of the slots of the antenna, with planar portions of the each Rotman lens defining a portion of each one of the slots of the antenna.

Abstract: A spatial filtering surface includes a dielectric substrate and a plurality of spaced, resonant dipole elements positioned on the dielectric substrate. Each dipole element has dipole ends and an associated diode for controlling amplitude taper and a reflection phase of an electromagnetic field at a selected frequency with respect to an angle of incidence to the dielectric substrate. Bias lines interconnect the dipole elements for conducting a bias current to a dipole element.

Abstract: A reflectarray antenna with a scanned radiated beam has an antenna feed for radiating a wave. A reflecting surface excited by the wave is reflected from a reflecting surface located on a tunable substrate in accordance with a variable surface impedance of the tunable substrate modulated to scan the radiated beam. The tunable substrate surface impedance is varied by modulating the dielectric constant or the permeability. The tunable substrate may be an electromagnetic band gap (EBG) material electromagnetic crystal (EXMT) structure to vary the surface impedance. The reflecting surface may be located on short-circuited waveguides with a variable surface impedance modulated to scan the radiated beam by adjusting phase shifts of the waveguides with tunable substrate phase shifter located in the waveguides or by adjusting the position of a piezoelectric movable short.

Abstract: An antenna system is provided with an antenna panel 1 which has fine bumps and dips 4 formed on a mirror surface side, which is one of surfaces opposing to each other, by etching, wherein the fine bumps and dips scatter sunlight entering the mirror surface side of the antenna panel 1 to suppress the collection of the sunlight and regularly reflect radio waves having longer wavelength than the sunlight entering the mirror surface side of the antenna panel.

Abstract: Optical modulators are provided. A representative optical modulator includes an optical medium that is adapted to propagate optical signals. An array of lattice sites are arranged in the optical medium, with at least some of the lattice sites exhibiting lower refractive indexes than the refractive index of the optical medium. Preferably, a first of the lattice sites incorporates a first optical component that is moveable relative to the optical medium. By moving the first optical component relative to the optical medium, a propagation characteristic of the optical medium can be altered. Optical systems, methods and other optical modulators also are provided.

Abstract: Composite media having simultaneous negative effective permittivity and permeability over a common band of frequencies. A composite media of the invention combines media, which are either themselves separately composite or continuous media, having a negative permittivity and a negative permeability over a common frequency band. Various forms of separate composite and continuous media may be relied upon in the invention. A preferred composite media includes a periodic array of conducting elements that can behave as an effective medium for electromagnetic scattering when the wavelength is much longer than both the element dimension and lattice spacing. The composite media has an effective permittivity &egr;eff(&ohgr;) and permeability &mgr;eff(&ohgr;) which are simultaneously negative over a common set of frequencies. Either one or both of the negative permeability and negative permittivity media used in the invention may be modulable via external or internal stimulus.

Abstract: Dielectric lenses (6) with an outer dimension of about 0.5 to 1.5 times a wavelength are arranged on front faces of respective slots (3) of a waveguide slot array antenna (1). The dielectric lenses (6) are formed in a panel structure where they have been connected integrally through a dielectric panel (7) so that they cover a front face of the antenna. Spherical waves radiated from the slots are converted into a flat wave by the dielectric lenses, and a composite wave of radiation waves from the respective slots becomes a flat wave which hardly includes ripples, so that an antenna gain is remarkably improved as compared with a case that dielectric lenses are not provided.

Abstract: A compensated radome is provided, comprising an inner layer of a negative index of refraction material, often referred to as a “metamaterial”, and an outer layer of a positive index of refraction material. The thickness of the two materials and their respective refractive indices are adjusted so that a beam of light passing through the radome is effectively not refracted. The metamaterial-compensated radomes solve the bore sight angle problem with a minimum of complexity.

Abstract: A dielectric lens antenna (100) includes a dielectric lens unit (101) having a plurality of cavities (106) and at least one fluidic dielectric having a permittivity and a permeability. The antenna further includes at least one composition processor (104) adapted for dynamically changing a composition of the fluidic dielectric to vary at least one of among the permittivity and the permeability in any of the plurality of cavities and a controller (102) for controlling the composition processor to selectively vary at least one of the permittivity and the permeability in at least one of the plurality of cavities in response to a control signal (105).

Abstract: A multi-band artificial magnetic conductor (AMC) is described in an electrically small antenna for use in handheld wireless devices and base station antenna applications. The multi-band AMC contains a ground plane, two or more frequency selected surfaces (FSS) having periodic conductive patches disposed on opposing surfaces and a dielectric layer sandwiched between the surfaces, and dielectric layers between the FSS layers and between the lower FSS layer and the ground plane. Various parameters of the dual band AMC are chosen such that the AMC has non-harmonically related resonant frequencies within two or more different frequency bands.