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:
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:
An electromagnetic energy concentrator uses a prism and waveguide with a gap layer of uniform thickness disposed between the prism and a first surface of waveguide. Energy detectors, which may be photovoltaics or miniaturized antenna elements are disposed adjacent to and co-extensive with a second surface of the waveguide. The detectors operate in each of at least two bands; a distance between detectors operating in a given band depends on a wavelength in the given band.
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:
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 solar energy collector includes a prism coupled waveguide and a cladding material layer coextensive with the waveguide core. Photovoltaics (PVs) are disposed within the cladding layer, with the PVs active in at least two wavelength ranges. The PVs are further spaced apart depending upon their active wavelength range. The cladding layer may include two or more material layers of at least two different dielectric constants. In that arrangement, the PVs are further grouped such that the PVs disposed in a first one of the cladding layers has a different active wavelength range than an active wavelength range of the PVs disposed in a second cladding layer.
Abstract:
A planar fixed area thin film antenna-coupled metal-insulator-metal (MIM) rectifier of arbitray metal with a native nickel oxide insulator. Devices can be designed for millimeter wave, IR, NIR and visible wavelengths.
Abstract:
A rectifier comprising a metal-insulator-metal (MIM) structure. The insulator may be a native oxide with an adjacent layer of graphene. In one implementation, the rectifier is used in an electromagnetic energy collector consisting of a planar waveguide formed of multiple material layers having at least two different dielectric constants. MIM rectifiers are aligned with mirrors are formed within the waveguide core. In some arrangements, a plurality of MIM rectifiers are disposed in a column or 3D array beneath each mirror.
Abstract:
An electromagnetic energy collector includes a planar waveguide formed of multiple material layers having at least two different dielectric constants. Mirrors formed within the waveguide core. Metal-insulator-metal (MIM) detectors are aligned with the mirrors, and disposed below the bottom surface of the waveguide. The mirrors may be etched at an angle into the waveguide. In some arrangements, wherein a plurality of MIM detectors are disposed in a column or 3D array beneath each mirror. A wavelength range of the MIM detectors disposed closer to a respective mirror is lower than a wavelength range of a MIM detector disposed farther away from the same mirror.