Abstract: An apparatus for removing flexible material from rotating equipment includes a cutter assembly integrated into the rotating equipment. The cutter assembly includes a cutter shaft, a cutter blade coupled to the cutter shaft, and a movement mechanism configured to move the cutter assembly along an axis of the rotating equipment to cut accumulated material from the rotating equipment.

Abstract: A low profile non-resonant traveling wave slot antenna operating over broad frequency bands is in the form of a multiple layer circuit, which includes a generally planar slotted conductor sheet having an open smoothly curved tapered planar slot therein and a three-dimensionally smoothly curved stripline conductor sheet having an elongated stem portion electrically connected at its distal end to a feed point on top of the slotted conductor sheet and extending downwardly through the slot therein and terminating in an enlarged smoothly tapered portion to transition the characteristic impedance between the feed point and an aperture impedance matched to free space.

Abstract: Resonant, end fire antennae that operate over broad frequency bands with a boosted gain at a preferred frequency, that can be incorporated into arrays, and that have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The transmission line and the conductor each have a quarter wavelength tuning stub connected thereto to boost the gain of the antenna at a predetermined frequency. The conductor and the sheath are terminated either with ground connections or by inductive loads.

Abstract: Non-resonant, end fire antennae that operate over broad frequency bands, can be incorporated into arrays and have low RF cross-sections are constructed from a transmission line, usually a piece of coaxial cable that if it is not self supporting, is mounted on or in a lightweight structural material with an outer end with a sheath or stripline the shape of half of a notch. The other half of the notch is formed from a conductor electrically connected to the center conductor of the coaxial cable. The cable and conductor are variably spaced to transition the characteristic impedance of the cable to that of free space. The conductor and the sheath are terminated either with ground connections or by inductive loads.

Abstract: A multimode low-profile avionics antenna is disclosed for use in Automatic Direction Finder (ADF) systems. The low profile antenna generates a steerable cardioid radiation pattern having a minimum bandwidth of 30% and an unusual degree of independence from mutual coupling and coupling to ground-plane currents. The antenna includes two resonant cavity-backed slot antennas. The upper cavity, which backs a directional crossed-slot antenna, is the larger of the two cavities. The shallow lower cavity is actually a short-circuited radial transmission line employing a stepped inner radius and band-switching to extend the operating bandwidth to the required 30%. The crossed-slot antenna elements are configured orthogonally and the slot ends are folded over the side of the cylindrical cavity to minimize the resonant cavity diameter for the requisite slot length.

Abstract: A system for correcting phase errors in a space based radar system utilizing probes located in front of an array of lens elements of a phased array antenna. Included is a mechanism for supplying a stored perfect value signal indicative of the distance between the probes and lens elements for a perfect, nondeformed array, and the mechanism for receiving radiated pilot signals to supply an actual value signal indicative of the actual distance between the probes and the lens elements to determine an amount of structural deformation. A mechanism is provided for measuring the difference in phase between the perfect value signal and the actual value signal to supply a deformation phase correction signal to adjust the beam steering command to correct for phase error introduced as a result of the measured structural deformation. Further disclosed is a system and method for effecting phase coherence across the array by utilizing a radiated reference pilot frequency pulse to each lens element.

Abstract: A scanning antenna comprises a non-magnetic, electrically conductive radiation horn defining an antenna opening having a predetermined central line of focus, and at least one magnetically switchable conductive element such as a reed relay mounted to extend across the antenna opening perpendicular to and spaced from the central line of focus. A magnetic field generator such as an electromagnet is positioned to generate a magnetic field to control switching of the conductive element between its conductive and non-conductive states, and a control circuit controls operation of the magnetic field generator.

Abstract: The radiation pattern of a beam at elevation angles near the horizon is improved for phased array antennas by control of the radiation field intensity near the horizon to reduce multipath disturbances, and to improve the axial ratio of a circularly polarized phased array antenna. This is accomplished by placing a parasitic phase shifting element directly below the antenna beam axis. The waveguide section is designed to produce a phase shift in the portion of antenna radiation energy passing through it to cancel some of the radiation energy in the direction of the horizon. The spacing of the waveguide section in front of the antenna is determined empirically for optimum results, i.e., for reduction of beam power below about 20.degree. without affecting beam power at high elevation angles.

Abstract: A multiple-feed Luneberg lens scanning antenna system. A Luneberg lens disposed for rotation. A first antenna feed is connected to and defines a first feed point on the surface of the lens. A plurality of second antenna feeds are respectively connected to and define a plurality of second feed points outside and closely adjacent the periphery of the lens. Supporting structure separately supports each of the second feeds at positions independent of the rotation of the lens. A drive system is coupled to the supporting structure for separately positioning each of the second feeds. The drive system also is coupled to the lens for rotating the lens to cause the first feed point to scan over a wide angle.