Abstract: A Nuclear Quadrupole Resonance detection system with features that include: a) slab radiating structure for the transmit path; b) reduced impedance transmit radiator; c) portal-embedded stripline couplers for receive path; d) wideband chirps each encompassing multiple simultaneous resonances; e) chirp sequencing enabling three channel architecture; f) magnetic amplification effect of ferrite-based directional couplers; g) determining position of substance within portal.

Abstract: Techniques for implementing series-fed antenna arrays with a variable dielectric waveguide. In one implementation, coupling elements with optional controlled phase shifters are placed adjacent each radiating element of the array. To avoid frequency sensitivity of the resulting array, one or more waveguides have a variable propagation constant. The variable waveguide may use certain materials exhibiting this phenomenon, or may have configurable gaps between layers. Plated-through holes and pins can control the gaps; and/or a 2-D circular or a rectangular travelling wave array of scattering elements can be used as well.

Abstract: A low profile antenna using a cavity-backed central radiating surface surrounded by one or more ground plane surfaces. Passively reconfigurable structure provide frequency dependent coupling between the surfaces. The frequency dependent couplings may be implemented using meander line structures, Variable Impedance Transmission Lines (VITLs), or tunable VITLs that used interspersed electroactive sections.

Abstract: A cylindrically symmetric satellite antenna that provides directional and omnidirectional operating modes in a compact form factor. Feed points located at the top of the cylindrical structure provide increased platform isolation. Combining networks, disposed below or within the cylindrical structure, may be replaced with inexpensive baluns composed of coaxial line sections.

Abstract: Techniques for implementing series-fed antenna arrays with a variable dielectric waveguide. In one implementation, coupling elements with optional controlled phase shifters are placed adjacent each radiating element of the array. To avoid frequency sensitivity of the resulting array, one or more waveguides have a variable propagation constant. The variable waveguide may use certain materials exhibiting this phenomenon, or may have configurable gaps between layers. Plated-through holes and pins can control the gaps; and/or a 2-D circular or a rectangular travelling wave array of scattering elements can be used as well.

Abstract: Dispersive properties of a linear dispersive delay line are retained in a spiral configuration by constraining the radius of curvature depending on a desired propagation mode. The compact form factor spiral can be either a continuous spiral or a piecewise linear approximation. The spiral comprises a highly dielectric waveguide such as titanium dioxide or barium tetratitanate. Preferably, a spacer with a low dielectric constant and a microstrip are disposed on the top surface. The microstrip prevents attenuation of low frequencies, thereby increasing the operating frequency range. A second dielectric spacer and a second microstrip can be deposited on the bottom surface of the waveguide. Alternatively, the bottom surface of the waveguide can face a ground plane. The waveguide can be fed by horns or half-horns.

Abstract: A structure or method for detecting a substance using conductive surfaces. Segments of conductive wire are disposed adjacent each of the surfaces and multi-turn coils are also disposed between the two surfaces, typically such that the windings of the coils are disposed between the respective conductive wires and the surfaces. A linear chirp signal, is applied to the wire segments. With the coils deactivated, emissions from the wire induce the Nuclear Quadrupole Resonance (NQR). With the coils activated to generate a static magnetic field, emissions from the wire induce Nuclear Magnetic Resonance (NMR). As a result, the characteristics of a substance located between the conductive surfaces may be determined using either or both resonant modalties.

Abstract: A system that uses the nuclear quadrupole resonant effect to detect the presence of materials of interest, such as may be excited by radio frequency fields generated within a portal. Transmitted chirp signals may be processed using matching filtering and other signal processing to accurately detect the presence of such materials.

Abstract: Nuclear quadrupole resonance measurement using two or more wire loop(s) within a space to define a portal, and driving the wire loop(s) with a baseband digital transmitter generating a chirped or stepped signal, to create a corresponding varying electromagnetic field within the portal. Coherent emissions reflected thereby are detected through a directional coupler feeding the transceiver. The detected coherent emissions are processed with a matched filter to determine presence of a target object within the portal.

Abstract: An antenna formed from one or more structures with sets of radiating elements oriented in four different, preferably orthogonal, directions. The radiating elements are further provided as multiple horizontal and vertical radiating section. The structure may be a six sided cube-like structure or a cylinder. A combining circuit provides omnidirectional, directional, and scanning/direction finding modes across a broad operating frequency range with multiple polarizations. The arrangement lends itself to implementation as a whip form factor well suited for vehicular applications.

Abstract: An orientation independent antenna apparatus using a six sided conductive structure and triangular elements on a selected surface thereof, to provide both horizontal and vertical polarization mode feeds. In one implementation, a vertical coupling element is disposed within the structure so that four perpendicular surfaces are parasitically coupled to provide the vertical polarization mode. In other implementations, coaxial cable(s) may be used with a ferrite core and/or combiner circuits to provide the horizontal mode feed.

Abstract: Detection of objects such as a buried explosive device while operating from a moving platform using a radio frequency emission system having two modes. An electromagnetic wave emission and detection system operates in a first mode to locate objects of interest and in a second mode to determine if an object contains explosive materials. In the first mode, the emission and detection system preferably operates as a subwavelength focusing, wideband, superlens using a near field super gain synthetic aperture continuous wave (CW) swept radar. In the second mode the system preferably enabled after detection of an object in the first mode, uses chemical detection methods such as Nuclear Quadrupole Resonance (NQR).

Abstract: System and methods for detecting substances such as explosives via the nuclear quadrupole resonance effect. We observe that the nuclear quadrupole resonances of explosives located within a cavity portal involve continuous Rabi transitions which are nonlinear processes since stimulated emission occurs. In other words, where there are no resonances caused by the presence of an explosive, high average power and low average power measurements should be identical. However, when resonances are stimulated by the system, the difference between these two conditions can be compared to determine a correction to measurements made when a person located in the cavity has explosive material on their person, without the need for separate empty portal or elaborate calibration procedures.

Abstract: Nuclear quadrupole resonance measurement using two or more wire loop(s) within a space to define a portal, and driving the wire loop(s) with a baseband digital transmitter generating a chirped or stepped signal, to create a corresponding varying electromagnetic field within the portal. Coherent emissions reflected thereby are detected through a directional coupler feeding the transceiver. The detected coherent emissions are processed with a matched filter to determine presence of a target object within the portal.

Abstract: System and methods for detecting substances such as explosives via the nuclear quadrapole resonance effect. We observe that the nuclear quadrupole resonances of explosives located within a cavity portal involve continuous Rabi transitions which are nonlinear processes since stimulated emission occurs. In other words, where there are no resonances caused by the presence of an explosive, high average power and low average power measurements should be identical. However, when resonances are stimulated by the system, the difference between these two conditions can be compared to determine a correction to measurements made when a person located in the cavity has explosive material on their person, without the need for separate empty portal or elaborate calibration procedures.

Abstract: A touch screen, now incorporated in most smart phones, presents an effective and transparent method to incorporate continuous active user verification schemes. The projected capacitive grid structure can be used to capture enough information to verify that a valid user currently has possession of the mobile device, even while the user is not consciously engaged in an active verification interface. Further processing, such as habitual gesture recognition, can augment the process.

Abstract: A leaky travelling wave array of optical elements provide a solar wavelength rectenna.

Abstract: Dispersive properties of a linear dispersive delay line are retained in a spiral configuration by constraining the radius of curvature depending on a desired propagation mode. The compact form factor spiral can be either a continuous spiral or a piecewise linear approximation. The spiral comprises a highly dielectric waveguide such as titanium dioxide or barium tetratitanate. Preferably, a spacer with a low dielectric constant and a microstrip are disposed on the top surface. The microstrip prevents attenuation of low frequencies, thereby increasing the operating frequency range. A second dielectric spacer and a second microstrip can be deposited on the bottom surface of the waveguide. Alternatively, the bottom surface of the waveguide can face a ground plane. The waveguide can be fed by horns or half-horns.

Abstract: A system that uses the nuclear quadrupole resonant effect to detect the presence of materials of interest, such as may be excited by radio frequency fields generated within a portal. Transmitted chirp signals may be processed using matching filtering and other signal processing to accurately detect the presence of such materials.

Abstract: A leaky travelling wave array of optical elements provide a solar wavelength rectenna.