Abstract: An antenna assembly includes an antenna and a radome that covers the antenna. The radome can be single- or double-walled, and, to prevent accumulation of dew on the radome, a radome heater operates to heat the radome's surface temperature in a relatively uniform manner by raising the radome air space's air temperature. To increase the radome heater's energy efficiency, an insulating layer thermally insulates the radome heater from the surface on which it is mounted.

Abstract: A first set of screws secures a Cassegrain-configuration microwave antenna's primary reflector to its low-noise block down-converter without additionally securing that reflector or the low-noise block down-converter to the antenna's feed tube, which a second set of screws separately secures to the low-noise block down-converter.

Abstract: The invention relates to an asymmetric optical fiber that includes a core and a functional cladding that surrounds substantially half of the core along at least a portion of the fiber. The asymmetric optical fiber may include substantially parallel electrodes disposed on a face of the optical fiber.

Abstract: An antenna assembly includes an antenna and a radome that covers the antenna. The radome can be single- or double-walled, and, to prevent accumulation of dew on the radome, a radome heater operates to heat the radome's surface temperature in a relatively uniform manner by raising the radome air space's air temperature. To increase the radome heater's energy efficiency, an insulating layer thermally insulates the radome heater from the surface on which it is mounted.

Abstract: A method is described for reducing the effect of linear birefringence in an optical fiber, in particular a circular-cored single-mode fiber. The invention may also be directed to an optical fiber having a reduced linear birefringence. A length of the optical fiber may be subdivided into a plurality of sections and a twist having a predetermined sense of rotation and a twist angle may be introduced between the sections. Fibers of this type may find applications, for example, in fiber-optic current and magnetic field sensors.

Abstract: A stacked patch antenna has a first element having a feed thereto spaced above a ground plane and one or more spaced apart parasitic elements spaced above the first element. The first and parasitic elements may be tuned to a fundamental mode for radiation of a specified frequency. The geometric centers of the parasitic elements are offset from one another and from the geometric center of the first element along the same direction. The stacked patch configuration provides increased gain and bandwidth. The offset configuration determines the direction of maximum gain for the antenna. The first and parasitic elements can be single antenna elements and may be microstrip antenna elements. The elements can also be arrays of microstrip antenna elements. The phasing of the arrays of microstrip elements can be controlled to determine a gain sensitivity direction.

Abstract: Disclosed are systems, methods, and an apparatus that includes a microstrip network disposed on a ground plane and including at least one collection point, where the collection point(s) is in electrical communication with the microstrip network, a probe associated with each collection point, the probe extending through at least one opening in the ground plane and in electrical communication with one or more transmission line(s), and, a physical perturbation associated with each probe, the physical perturbation integrated with the transmission line(s) to create at least a first and a second signal port in the transmission line(s).

Abstract: Disclosed are methods, systems, and a device that includes an output for providing at least a first signal at a first frequency and a distinct second signal at a distinct second frequency, a first signal channel connected between a first waveguide port and the output, the first waveguide port providing a harmonic of the first signal, and, a distinct second signal channel connected between a second waveguide port and the output, the second waveguide port providing a harmonic of the second signal, where the first signal channel includes a notch filter centered substantially at the distinct second frequency, and the second signal channel includes a notch filter centered substantially at the first frequency.

Abstract: Disclosed are systems, methods, and an apparatus that includes a microstrip network disposed on a ground plane and including at least one collection point, where the collection point(s) is in electrical communication with the microstrip network, a probe associated with each collection point, the probe extending through at least one opening in the ground plane and in electrical communication with one or more transmission line(s), and, a physical perturbation associated with each probe, the physical perturbation integrated with the transmission line(s) to create at least a first and a second signal port in the transmission line(s).

Abstract: A feed network for, and method of feeding, an array of antenna elements has multiple feed points. Two feed lines extend from the feed points, one having a longer length that the other to provide a phase difference in the two feed lines. The feed lines split into main feed lines, which in turn split into secondary feed lines that connect to the antenna elements. The connections to the elements fed from one of the feed lines are rotated with respect to the connections to the elements fed from the other to provide another phase difference between the elements. The antenna elements may be fed from the longer of the feed lines from one of the feed points and the shorter of the feed lines from an adjacent feed point, with the connections from the feed points providing for right hand and left hand circular polarized elements, respectively.

Abstract: A method and device for measuring the current in a conductor are presented. They utilize the Faraday effect on counter-propagating circularly polarized beams of light in a fiber optic coil. The light beams are transformed to and from circular polarization by a polarization transformer comprised of a birefringent fiber with a twist through an appropriate angle at an appropriate distance from one end.

Abstract: The present disclosure is in part directed to optical devices for modulating light comprising compounds which spontaneously align. The disclosure is also directed to electro-optic compounds wherein chromophore substituents are chemically bound to a chiral polymer. In one embodiment, the chiral polymer comprises a binaphthyl monomeric unit.

Abstract: A feed network for, and method of feeding, an array of antenna elements has multiple feed points. Two feed lines extend from the feed points, one having a longer length that the other to provide a phase difference in the two feed lines. The feed lines split into main feed lines, which in turn split into secondary feed lines that connect to the antenna elements. The connections to the elements fed from one of the feed lines are rotated with respect to the connections to the elements fed from the other to provide another phase difference between the elements. The antenna elements may be fed from the longer of the feed lines from one of the feed points and the shorter of the feed lines from an adjacent feed point, with the connections from the feed points providing for right hand and left hand circular polarized elements, respectively.

Abstract: The invention comprises a system and method for reducing a shot noise component of the Angle Random Walk Noise in a fiber optic sensor by providing a first optical amplifier prior to the photodetector of the sensor to increase the power seen at the detector. An optical amplifier and second detector may be provided to detect a source sample, which can be useful in reducing RIN noise. Optical isolators may be added at the optical amplifiers to prevent rear facet emissions from the optical amplifiers from affecting sensor signals. A coupler with an isolator, amplifier and detector may be provided to receive a sample of the facet emissions from the first optical amplifier, which may be subtracted from the sensor signal at the detector so as to eliminate the facet emissions from the sensor signals. Polarizers may be provided prior to each detector to further eliminate emissions.

Abstract: The invention is directed to an apparatus and a method for reducing noise, in particular RIN noise, in optical sensors, in particular fiber-optic sensors. The optical sensor produces a sensor output signal representing a physical quantity to be measured and also contains a first noise component, which is detected by a first detector. A separate detector detects an input light noise component of the input light source of the optical sensor and produces a second noise component. The second noise component is electronically processed and time-delayed by a filter by a time delay which substantially corresponds to the time delay experienced by the sensor input light traversing the optical sensor. The time-delayed processed signal is then subtracted from the sensor output signal to produce a reduced noise optical sensor signal corresponding to the measured physical quantity.

Abstract: A stacked patch antenna has a first element having a feed thereto spaced above a ground plane and one or more spaced apart parasitic elements spaced above the first element. The first and parasitic elements may be tuned to a fundamental mode for radiation of a specified frequency. The geometric centers of the parasitic elements are offset from one another and from the geometric center of the first element along the same direction. The stacked patch configuration provides increased gain and bandwidth. The offset configuration determines the direction of maximum gain for the antenna. The first and parasitic elements can be single antenna elements and may be microstrip antenna elements. The elements can also be arrays of microstrip antenna elements. The phasing of the arrays of microstrip elements can be controlled to determine a gain sensitivity direction.

Abstract: A feed network for, and method of feeding, an array of antenna elements has multiple feed points. Two feed lines extend from the feed points, one having a longer length that the other to provide a phase difference in the two feed lines. The feed lines split into main feed lines, which in turn split into secondary feed lines that connect to the antenna elements. The connections to the elements fed from one of the feed lines are rotated with respect to the connections to the elements fed from the other to provide another phase difference between the elements. The antenna elements may be fed from the longer of the feed lines from one of the feed points and the shorter of the feed lines from an adjacent feed point, with the connections from the feed points providing for right hand and left hand circular polarized elements, respectively.

Abstract: A method for incorporating an optical material into an optical fiber and optical devices utilizing the method are disclosed. Fiber material may be removed from the optical fiber to expose the fiber core and the core may then be at least partially removed. The optical material may then be incorporated into the core area to replace the removed core. Cladding material may then be deposited over the optical material and an electrode may be fixed to the cladding over the optical material to form an optical device.

Abstract: The invention relates to the field of fiber optics, and more particularly to birefringence in single-mode fibers. The sensitivity of a fiber optic sensor coil for a current sensor may be increased by winding the sensing fiber, without torsion, around a current-carrying wire to form the coil, wherein the pitch angle of the fiber may be selected to result in a phase shift due to Berry's phase of circularly polarized light propagating through the fiber. Preferably, the pitch angle may be approximately 60°.