Abstract: A directional antenna made with photonic band gap structures has been presented. The directional antenna is formed with two photonic band gap structures oriented back to back and separated from each other by a distance to form a resonant cavity between the photonic band gap structures. An antenna element is placed in the resonant cavity. The resonant frequency of the cavity is tuned by adjusting the distance between the photonic band gap structures. The resonant cavity can be asymmetrical or symmetrical.

Abstract: An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

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: A high performance multi-band antenna reflector having low sidelobe and cross polarization levels, and a superior carrier-to-interference ratio has two concentric zones (12, 14 in a first embodiment and 102, 104 in a second embodiment). In the first embodiment, the outer concentric zone (14) is a frequency selective absorber (20) made of a metallic pattern (22) dimensioned to reflect signals in one frequency band and absorb signals in a second frequency band. In the second embodiment, the outer concentric zone (104) is a frequency selective surface (106) that reflects signals in one frequency band and passes signals in a second frequency bands. Resistance cards (122) overlay the top and bottom sides of the junction between the frequency selective surface (106) and a reflective layer (110) on an inner surface (112) of the central concentric zone (102).

Abstract: A high impedance (Hi-Z) wire effectively transparent to electromagnetic radiation polarized in the direction of the wire, within an operating frequency band. The Hi-Z wire is sheathed with a thin layer of resonant structures that are small compared to the wavelength, and behave as a kind of photonic band gap (PBG) material. A frequency-selective polarizer comprising a plurality of Hi-Z wires disposed parallel to one other in a grid. A wire grid reflector that enables stepwise phase control of the reflected wave and focusing of radiative power, the reflector comprising Hi-Z wires interspersed with conventional wires disposed parallel to one another in a grid.

Abstract: An artificial anisotropic dielectric material can be used as a microstrip patch antenna substrate. The artificial dielectric can be easily designed for the purpose of weight reduction. Preferably, the artificial dielectric is comprised of a periodic stack of low and high permittivity layers. The layers can be oriented vertically below the patch to support electric fields consistent with desired resonant modes. Substrates may be engineered for both linearly and circularly polarized patch antennas. Antenna weight can be reduced to ⅙th up to {fraction (1/30)}th of the original weight using different types of high permittivity layers. This concept has numerous applications in electrically small and lightweight antenna elements such as PIFA antennas. In accordance with one aspect of the invention, the artificial dielectric is comprised of an interlocking structure of low and high permittivity layers for ease of assembly and for overall stability.

Abstract: An antenna apparatus such that a dielectric strip and a dielectric resonator are provided to form a primary vertical radiator, another dielectric strip is provided which is coupled to the dielectric strip to form a directional coupler, and a radiation beam is tilted by changing the relative position of the primary radiator with respect to the dielectric lens by displacing the primary vertical radiator in the directional coupler.

Abstract: A composite antenna reflector architecture for improving beam-to-beam isolation in a multi-spot illuminated reflector antenna employs a plurality of annular rings surrounding a central reflective dish and having respectively different controlled reflectivity profiles. The reflectivity-tailored reflector rings alter illumination taper and reduce selected sidelobe energy, and minimize degradation in coverage performance and gain slope in the radiation profile of the antenna. A respective ring employs a frequency selective surface laminate of layers containing different elements that resonate at different frequencies spectrally spaced to provide at least one composite frequency response characteristic.

Abstract: An electronic device for distorting sensitive information in one or more electromagnetic emanations from the electronic device is disclosed. The device has one or more active layers having one or more electronic components that emit the electromagnetic emanations and one or more conductive substrate layers planarity adjacent to one or more of the active layers that distort the electromagnetic emanations. In alternative embodiments of the inventions, shielding is added with frequency selective openings. In other alternative embodiments, a signal source is added to distort sensitive information.

Abstract: The present invention relates to planar materials having bandgap properties. The materials are formed by depositing conductive fractal patterns on a non-conducting substrate. The bandgap location(s) are defined by parameters including the number of fractal levels, and the dimension of the fractal mother element. The bandgaps can also be actively controlled by injecting current into the conducting pattern.

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: Methods and systems are provided for embedding electrical components within a device including a frequency responsive structure, such as an antenna or a frequency selective surface. Electrical components are selected and locations for placing the selected components within the device are selected for optimizing performance characteristics of the structure. The selection may be performed by modeling the device with various electrical components embedded at various locations using, for example, a genetic algorithm. The selected components are embedded at the selected locations. The frequency responsive structure and the selected components embedded at the selected locations may be produced in the same manufacturing process. The selected electrical components may be embedded at the selected locations as contiguous and integral parts of the device and may be embedded within the frequency responsive structure.

Abstract: A tuneable impedance surface for steering and/or focusing a radio frequency beam. The tunable surface comprises a ground plane; a plurality of elements disposed a distance from the ground plane, the distance being less than a wavelength of the radio frequency beam; and a capacitor arrangement for controllably varying the capacitance of adjacent top plates, the capacitor arrangement including a dielectric material which locally changes its dielectric constant in response to an external stimulus.

Abstract: DC inductive FSS technology is a printed slow wave structure usable for reduced size resonators in antenna and filter applications of wireless applications. It is a dispersive surface defined in terms of its parallel LC equivalent circuit that enhances the inductance and capacitance of the equivalent circuit to obtain a pole frequency as low as 300 MHz. The effective sheet impedance model has a resonant pole whose free-space wavelength can be greater than 10 times the FSS period. A conductor-backed DCL FSS can create a DC inductive artificial magnetic conductor (DCL AMC), high-impedance surface with resonant frequencies as low as 2 GHz. Lorentz poles introduced into the DCL FSS create multi-resonant DCL AMCs. Antennas fabricated from DCL FSS materials include single-band elements such as a bent-wire monopole on the DCL AMC and multi-band (dual and triple) shorted patches, similar to PIFAs with the patch/lid being a DCL FSS.

Abstract: An antenna includes a probe capable of transforming electrical energy into electromagnetic energy and inversely. It further includes an assembly of elements made of at least two materials different in permittivity and/or permeability and/or conductivity within which the probe is arranged, the arrangement of the elements in the assembly ensuring radiation and spatial and frequency filtering of the electromagnetic waves produced or received by the probe, which filtering allows in particular one or several operating frequencies (f) of the antenna inside a frequency band gap (B).

Abstract: An antenna system for receiving both circularly polarized electromagnetic signals and linearly polarized electromagnetic signals, the circularly polarize signals arriving at the antenna system from a direction normal or oblique to a major surface of the antenna system and the linearly polarized signals arriving at the planar antenna system from a direction acute to said major surface. The antenna system includes a high impedance surface and a plurality of antenna elements disposed on said high impedance surface, the plurality antenna elements arranged in a pattern on said surface such first selected ones of said antenna elements are responsive to circular polarization and second selected ones of said antenna elements are responsive to linear polarization.

Abstract: A flat metal plate (20) has a plurality of holes (50) that have a property that changes across the surface of the plate so that the flat plate (20) mimics the behavior of a curved wavefront transformer. The changing property can include a dimension, such as radius or depth, such that the holes (50) near the center of the plate (20) are smaller, for example, than the holes (50) further away from the center of the plate (20). The size of each hole (50) is a function of the local phase change imparted on an electromagnetic wave of a particular wavelength or frequency that hits the hole (50), plus the propagation phase change that occurs in the reflected wave exiting the hole (50) as it travels the distance between the hole (50) and the focal point.

Abstract: A grating comprising a plurality of substantially parallel members having a conducting surface of depth L, separated by a dielectric layer gap, and having of pitch &lgr;g and where L>16&lgr;g. The members are preferably metallic or comprise metallic foil covered plastic. The gap may be filled wholly or partially with dielectric material including liquid crystal whose refractive index can be controlled by suitable application of voltage across the gap.

Abstract: A tuneable impedance surface for steering and/or focusing a radio frequency beam. The tunable surface comprises a ground plane; a plurality of elements disposed a distance from the ground plane, the distance being less than a wavelength of the radio frequency beam; and a capacitor arrangement for controllably varying the capacitance of at least selected ones of adjacent elements. A method of tuning the high impedance surface allows the surface to mimic, for example, a parabolic reflector or a diffraction grating.

Abstract: An antenna system for receiving both circularly polarized electromagnetic signals and linearly polarized electromagnetic signals, the circularly polarize signals arriving at the antenna system from a direction normal or oblique to a major surface of the antenna system and the linearly polarized signals arriving at the planar antenna system from a direction acute to said major surface. The antenna system includes a high impedance surface and a plurality of antenna elements disposed on said high impedance surface, the plurality antenna elements arranged in a pattern on said surface such first selected ones of said antenna elements are responsive to circular polarization and second selected ones of said antenna elements are responsive to linear polarization.

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 Lungberg 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: The present invention refers to an arrangement in an antenna, the arrangement comprising: an electrically thin microwave phasing structure including a support member, a reflective arrangement for reflecting microwaves within a frequency operating band and supported by said supporting member, and a phasing arrangement of electromagnetically-loading structures, said electromagnetically-loading structures being interspaced from each other and disposed at a distance from said reflective arrangement by a support matrix to provide said emulation of said desired reflective surface of selected geometry. The electromagnetically-loading structures are arranged on at least two substrate layers in at least two planes.

Abstract: An optimal configuration for at least one antenna and/or at least one frequency selective surface is generated. A configuration of elements is generated by selecting a simple configuration of at least one element and applying a genetic algorithm to the simple configuration to generate a configuration optimized for various characteristics. A stochastic process may be used to randomly select an arrangement of elements as the simple antenna configuration and to select elements that connect the randomly selected elements to produce a stochastic configuration to which the genetic algorithm is then applied. Alternatively, an iterated or semi-iterated process may be applied to the simple antenna configuration to produce a fractal or a semi-fractal configuration, respectively, to which the genetic algorithm is then applied. Also, the elements may be optimized independently.

Abstract: A 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: The present invention is directed to, in a first aspect, an antenna array stimulation system. In one embodiment the system comprises an array of radiating elements, a conductive layer adjacent the array of radiating elements adapted to receive electrical energy from, or couple electrical energy to, the array, and at least one connection device adapted to couple the electrical energy between the conductive layer and a test unit, wherein antenna performance degradation due to potential losses in coupling the energy between the conductive layer and the test unit are minimized.

Abstract: An artificial anisotropic dielectric material can be used as a microstrip patch antenna substrate. The artificial dielectric can be easily designed for the purpose of weight reduction. Preferably, the artificial dielectric is comprised of a periodic stack of low and high permittivity layers. The layers can be oriented vertically below the patch to support electric fields consistent with desired resonant modes. Substrates may be engineered for both linearly and circularly polarized patch antennas. Antenna weight can be reduced to ⅙th up to {fraction (1/30)}th of the original weight using different types of high permittivity layers. This concept has numerous applications in electrically small and lightweight antenna elements such as PIFA antennas. In accordance with one aspect of the invention, the artificial dielectric is comprised of an interlocking structure of low and high permittivity layers for ease of assembly and for overall stability.

Abstract: An artificial magnetic conductor is resonant at multiple resonance frequencies. The artificial magnetic conductor is characterized by an effective media model which includes a first layer and a second layer. Each layer has a layer tensor permittivity and a layer tensor permeability having non-zero elements on the main tensor diagonal only.

Abstract: A multi-band reflector antenna has a main reflector defining a prime focus and a frequency selective surface (FSS) sub-reflector defining an image focus. One or more transmitter or receiver feeds are provided at each of the prime focus and image focus. In one application as a ground satellite terminal, the antenna supports Ka-band two-way broadband Internet access bundled with multi-satellite Ku-band direct broadcast television service (DBS).

Abstract: A flexible antenna array comprises a plurality of layers of thin metal and a flexible insulating medium arranged as a sandwich of layers. Each layer of the sandwich is patterned as needed to define: (i) antenna segments patterned in one of the metal layers, (ii) an array of metallic top elements formed in a layer spaced from the the antenna segments, the array of metallic top elements being patterned in another metal layer, (iii) a metallic ground plane formed in a layer spaced from the array of metallic top elements, the metallic ground plane having been formed from still another metal layer, and (iv) inductive elements coupling each of the top elements in the array of metallic top elements with said ground plan. An array of remotely controlled switches are provided for coupling selected ones of said antenna segments together.

Abstract: The invention discloses a patch antenna structure in which a full transmission line is replaced by a set of transmission lines connected between two slots or radiative elements. Components can be inserted in the space between the transmission lines. In a second embodiment, the transmission lines are cranked or bended for a more compact dimension of transmission lines. The cranked or bended transmission lines can also be loaded by inductive elements. In a third embodiment, a patch antenna is constructed with n sets of transmission lines between the two slots, where each set of transmission line produces a different electrical length in accordance with a particular frequency. In a fourth embodiment, a set of intermediate filters is added within the transmission lines for differentiating the frequencies.

Abstract: An electromagnetic wave radar device mounted on a car, which helps improve external appearance of a car without impairing radar function, and is fabricated using a decreased number of parts at a reduced cost. The electromagnetic wave radar device comprises an electromagnetic wave radar body 1 mounted on a car 2 and for transmitting and receiving electromagnetic waves of a predetermined frequency, and a radome portion made of a material which permits the electromagnetic waves to transmit through and covers the electromagnetic radar body, the electromagnetic wave radar body being disposed on the side of the back surface 30A of the bumper 30 of the car, and the radome portion being formed by a portion of the bumper of the car.

Abstract: Provided is a composite dielectric molded product exhibiting excellent properties such as the antenna gain and side lobe, etc. when used for a lens antenna, and exhibiting less variation of properties in one individual product and between individual products. The composite dielectric molded product is formed by molding a composite dielectric material containing a dielectric inorganic filler and an organic polymer material so that the dielectric constant anisotropy is in the range of about 1.00 to 1.05.

Abstract: A dielectric lens is formed by laminating a plurality of dielectric sheets having different diameters along a focal axis of the lens. The first dielectric sheet is formed by injecting a dielectric material in a molten state at a predetermined pressure and cooling and solidifying the dielectric material. Each successive dielectric sheet is formed by injecting the dielectric material in a molten state on the preceding dielectric sheet and cooling and solidifying the dielectric material, so that each successive dielectric sheet and each immediately preceding dielectric sheet are fusion-bonded to each other.

Abstract: A reflector antenna system having a diplexer for providing isolation between transmitted and received signals, which eliminates the need for a diplexer to be inserted into the waveguide or coax transmission line coupling the antenna system with an external antenna electronics subsystem. The antenna system includes a main reflector to which is coupled a low effective dielectric tube. Transmit and receive feedhorns are supported within the tube. A hyperboloidal receive bandpass filter is supported in front of the receive feedhorn and a hyperboloidal transmit bandpass filter is disposed in front of the transmit feedhorn. The receive bandpass filter allows the received signal to pass therethrough but blocks the transmitted signal from the transmit feedhorn. Conversely, the transmit bandpass filter reflects the received signal received from the subreflector surface back towards the receive feedhorn while allowing the transmitted signal from the transmit feedhorn to pass therethrough.

Abstract: A band-gap spectral filter is made of a nanochannel glass structure having a two-dimensional array of parallel dielectric rods arranged in a matrix material. The materials for the dielectric rods and the matrix material are selected so that the difference between the refractive index of the dielectric rods and the refractive index of the matrix material is equal to or less than about 0.5.

Abstract: A high impedance surface having a reflection phase of zero in multiple frequency bands and a method of making same. The high impedance surface includes a ground plane; a plurality of conductive plates disposed in a first array spaced a distance from the ground plane, the distance being less than a wavelength of the radio frequency beam, said first array having a first lattice constant; and a plurality of conductive elements associated with said plurality of conductive plates, said plurality of conductive elements defining a second array, said second array having a lattice constant greater than the lattice constant of the first array.

Abstract: A tuneable impedance surface for steering and/or focusing a radio frequency beam. The tunable surface comprises a ground plane; a first plurality of elements disposed in an array a first distance from the ground plane, the distance being less than a wavelength of the radio frequency beam; and a second plurality of elements disposed in an array a second distance from the ground plane, the second plurality of elements be moveable relative to the first plurality of elements.

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: A frequency reconfigurable artificial magnetic conductor (AMC) includes a ground plane, a spacer layer disposed adjacent the ground plane and a plurality of vias in electrical contact with the ground plane and extending from a surface of the ground plane in direction of the spacer layer. The AMC further includes a frequency selective surface (FSS) disposed on the spacer layer and including a periodic pattern of bias node patches alternating with ground node patches, the ground node patches being in electrical contact with respective vias of the plurality of vias, and components between selected bias node patches and ground node patches, the components having a capacitance which is variable in response to a bias voltage. A network of bias resistors between adjacent bias node patches provides the tuning voltage.

Abstract: A cylindrical, ray-imaging, electronically steered array antenna, whose radiating array elements are disposed on a cylindrical surface sector above an electrically conductive ground plane that enhances the antenna gain. The conductive ground plane forms an integral part of the antenna, and the required dimensions of this ground plane depend on the array radius, and on the lowest elevation coverage angle from the (possibly tilted) ground plane. The antenna of the present invention is further characterized by a modular design that tailors the required antenna gain and azimuthal directivity through the stacking of identical antenna segments side by side. The antenna design uses the multiple-beam ray focusing property of a microwave lens when feeding a circular ring array, while producing at the same time coherent ray imaging from a bottom metal plate.

Abstract: A domed divergent microwave lens includes a plurality of waveguides with various lengths, the greatest length being that on the axis of the lens and the length being shorter for waveguides far from the axis. The axes of the waveguides are all parallel to each other and parallel to the axis of the lens, for example.

Abstract: A bandpass radome that reduces the number of spurious resonances, and that tends to suppress Transverse Magnetic TM and Transverse Electric TE surface waves, is described. In one embodiment, the radome includes an inductive FSS ground plane layer. First and second capacitive FSS layers are disposed above the inductive ground plane layer. Third and fourth capacitive FSS layers are disposed below the inductive ground plane layer. In one embodiment, the capacitive FSS layers use patch elements and some or all of the FSS patch elements above and below the inductive ground plane layer are electrically connected to the inductive ground plane layer by a conducting posts. The conducting posts form a rodded medium to suppress TM and TE surface waves. In one embodiment the total thickness of the bandpass radome is less than &lgr;/20 at the center frequency of the passband.

Abstract: A hood is provided for verifying the performance of the missile. The hood includes one or more sense antennas having the same polarization as the antennas within the missile to be tested. The hood further includes one or more elliptic-to-circular polarization converters designed to reduce the axial ratio of the signal received from the missile. The elliptic-to-circular polarization converters convert the signal from the missile to a substantially pure circular polarized signal which is then sensed by the sense antennas.

Abstract: A microwave device operating at a selected frequency band or group of selected frequency bands of interest includes a resonant bulk material having one or more conductivity bandwidths corresponding to the selected frequency band or group of selected frequency bands of interest. The resonant bulk material exhibits conductive properties at a frequency or frequencies within the one or more conductivity bandwidths and non-conductive properties at all other frequencies, and includes a narrowband metal material having a Lorentz resonance frequency or frequencies within the selected frequency band or group of selected frequency bands of interest.

Abstract: A beam forming low profile scanning antenna system is provided comprising a radiating element (11) for radiating signals and a pair of panels (13 and 15) each having an array of phase-inducing transmitting resonant elements (21) on a pair of panels for focusing said radiating signals to produce radiated beams. The panels are rotated with respect to each other (17) to scan said beams.

Abstract: The otherwise distorted pattern of an antenna disposed within an anisotropic radome (e.g. of a submarine) is corrected with a complementary anisotropic RF lens.

Abstract: The present invention relates to a crystal structure with three-dimensional photonic band gap which comprises a pile of alternate series of layers of distinct dielectric materials having a first and a second determined dielectric constant values, wherein said layers have a constant determined thickness and said pile forms a substantially rectangular parallelepipedal block, and a plurality of parallel channels provided through said block along a direction orthogonal to the main faces of said layers. Said channels are distributed according a two-dimensional lattice pattern and have a third determined dielectric constant value. The values for the dielectric constants as well as the relative geometric dimensions of said layers and said channels are selected so as to obtain said three-dimensional photonic band gap in a predetermined frequency range. The crystal structure is especially for use as an antenna substrate.

Abstract: A duplexer 24 comprising substantially semi-cylindrical filters 1 and 5 is disposed in and made integral with an increased diameter hollow stem part 29 of a substantially rod-like antenna element 22. The two filters 1 and 5 are coupled together by a coupler substrate 8 interposed between them. The coupler substrate 8 is disposed between the two filters 1 and 5 for forming a connector 23, which is connected to the antenna element 22. This assembly is connected by connector pieces 25 to 27 to a transmitter and a receiver part of a radio part of a portable telephone set or the like.

Abstract: An improved plasma controlled millimeter wave (MMW) or microwave (&mgr;W) antenna is provided. A plasma of electrons and holes is photo-injected into a photoconducting wafer. A special distribution of plasma and a MMW/&mgr;W reflecting surface behind the wafer allows the antenna to be generated at low light intensities and a 180° phase shift (modulo 360°) to be applied to selected MMWs/&mgr;Ws.

Abstract: An ultra-wideband, multi-beam adaptive antenna includes a phased array system having an ultra-wideband antenna. The antenna further includes at least two sub-arrays of antenna elements for receiving radio frequency (RF) signals located in a respective at least two sub-bands of a desired wide frequency band. The sub-arrays are interspersed to provide a single wideband antenna, which is coupled with a phased array system having multiple beamforming networks.