Abstract: A crossed-slot antenna is fabricated using rectangular sheet of metal. A crossed-slot is etched or stamped in the sheet of metal. A feed structure is similarly formed in the sheet of metal. Sidewalls are integrally formed with the sheet of metal and are bent to form a rectangular box. A circuit board is attached to the rectangular box. An air-filled cavity is defined by the sheet of metal, the sidewalls, and the circuit board. Alternatively, a crossed-slot antenna with a solid cavity is fabricated using a sheet of plastic. Ridges are formed in a cross pattern on the sheet of plastic. The sheet of plastic is plated with metal. The metal is removed from a surface of the sheet of plastic, exposing the ridges.

Abstract: A method of integrating a thin antenna module into a vehicle is disclosed. The thin antenna module comprises a high impedance surface with at least one antenna element disposed thereon. The method includes the steps of inserting the thin antenna module between a conductive layer and a dielectric layer located above a passenger compartment of said vehicle, and connecting at least one antenna element disposed on the high impedance surface to a receiver in said vehicle.

Abstract: A wideband wireless access local loop system using millimeter wavelength wireless technology to provide wireless access to a series of customer interfaces, via a series of access interface points, to a backbone network of central nodes interconnected by a high transmission-rate broadband medium such as fiber optic cable. The network architecture is useful for providing a two-way high-speed data transfer system to structures without the need for physical wiring. Data transfer within the network may optionally be either analog or digital, and may be optimized for either two-way communication or one-way distribution.

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: 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: The present invention provides an apparatus for and method of determining the nature of the wireless environment which is in use and dynamically selecting appropriate frequency channels for data transmissions which are more likely to accommodate sustained data transmission at high speeds.

Abstract: A method of integrating a thin antenna module into a vehicle is disclosed. The thin antenna module comprises a high impedance surface with at least one antenna element disposed thereon. The method includes the steps of inserting the thin antenna module between a conductive layer and a dielectric layer located above a passenger compartment of said vehicle, and connecting at least one antenna element disposed on the high impedance surface to a receiver in said vehicle.

Abstract: An improved low-angle radiation antenna is obtained through excitation of a tangential electric field on the high-impedance surface, as well as leaky transverse-electric surface waves. Such fields and surface waves cannot normally occur on an ordinary metal surface. The tangential electric field on the high-impedance region excites a transverse-magnetic surface wave on a surrounding metal surface which gives improved low-angle radiation in the E-plane of an antenna disposed on the high impedance surface. Leaky transverse-electric surface waves provide improved radiation in the H-plane of the antenna.

Abstract: A polarization converting surface for reflecting impinging radio frequency waves. The surface includes a ground plane and a plurality of elements disposed in an array a distance from the ground plane. Each element is preferably connected to the ground plane by a conductor, the array of elements having two major axes associated therewith. The elements have a first bandwidth corresponding to a first range of frequencies were a first reflection phase falls between −&pgr;/2 and +&pgr;/2 in a first one of said two major axes and a second bandwidth corresponding to a second range of frequencies were a second reflection phase falls between −&pgr;/2 and +&pgr;/2 in a second one of said two major axes. The first and second bandwidths partially overlap and preferably an upper half of one of the bandwidths overlies a lower half of the other one of the bandwidths.

Abstract: A method and apparatus for reconfiguring an antenna array by optical control of MEMS switches. A light source is provided to direct light to individual optically sensitive elements which control delivery of actuating bias voltage to the MEMS switches. The light source is preferably separated from the antenna array by a structure which conducts the controlling illumination but provides a high impedance electromagnetically reflective surface which reflects electromagnetic radiation over the antenna operating frequency range with small phase shift, and which is disposed very close to the antenna array. Optically sensitive elements preferably include photoresistive elements, which are best formed in the substrate upon which the MEM switches are formed, and may include photovoltaic elements.

Abstract: A directive antenna and method of directing a radio frequency wave received by and/or transmitted from the antenna. The antenna preferably includes a high impedance surface with a plurality of antenna elements disposed on said surface, a plurality of associated demodulators and power sensors and a switch. A Vivaldi Cloverleaf antenna is disclosed.

Abstract: An optical fiber dispenser (40) includes a bobbin (42), an optical fiber pack (52) overlying the bobbin (42), and a thermal expansion accommodation layer (50) positioned between the bobbin (42) and the optical fiber pack (52 ). The thermal expansion accommodation layer (50) is made of a material, such as a silicone elastomer, that is readily deformable to accommodate the different longitudinal coefficients of thermal expansion of the bobbin (42) and the optical fiber pack (52). The thermal expansion accommodation layer (50) has a thickness, typically more than about 1/8 inch for a conventional bobbin size, sufficient to reduce any thermal stresses produced by the different longitudinal coefficients of thermal expansion to less than the failure strength of the optical fiber pack (52).

Abstract: A fast and reliable switch (50) for multi-channel, bi-directional fiber optics data link (FODL) systems. The FODL channel switching is accomplished through a software command on the subcarrier frequency (SCF) code without using any moving components or wavelength sensitive optical devices. A fiber star coupler (92) and in-line erbium doped fiber amplifiers (94A-94Q) transform the FODL system into an electrically switchable, fiber star network with low optical power loss penalty. The switch can be used in multiple fiber optics guided missile launch systems and fiber optics based surveillance systems with multiple outposts. The switching scheme allows the launcher/controller (60) to perform a time-sharing control on multiple missiles (or outposts) (80-80P) by switching the SCF code sent to the programmable SCF generator of the OE unit in the controller (launcher).

Abstract: A bi-directional erbium doped fiber (EDF) optical fiber amplifier (50) employing two separate EDF amplifier channels (52, 62) for two counter-propagating signals allows the optimization of each individual signal channel for efficient bi-directional optical signal repeater performance. The pump sources (53, 63) for each EDF channel (52, 62) can be switched on and off independently, to serve as an in-line signal switch, without affecting another signal channel.

Abstract: A tethered vehicle such as a missile system comprises a tethered vehicle body having a control system and propulsion system therein, a control station for the tethered vehicle located outside of the tethered vehicle body, and an optical fiber data link extending from the tethered vehicle control system to the control station. The tethered vehicle system further includes a GPS positioning system for the tethered vehicle, which comprises a positioning signal receiving antenna mounted in the tethered vehicle, and a positioning signal amplifier mounted in the tethered vehicle, which receives a positioning signal from the antenna and produces an amplified positioning signal. A transmitter transmits the amplified positioning signal into the optical fiber data link at its end within the tethered vehicle, and a receiver receives the amplified positioning signal from the optical fiber data link at its end at the control station. A signal processor analyzes the amplifier positioning signal received from the receiver.

Abstract: A continuous filament (40) from a supply spool (50) is wound onto a takeup spool (52) in an amount to form one flat coil (54). A first winding device (42) forms a first flat coil (54) in winding space (36) between guides (28 and 30) while simultaneously a second winding device (44) winds a second flat coil in winding space (38) between guides (30 and 32) from the filament on the takeup spool (52). On completion of the flat coil winding, the guide (32), second winding device (44) and takeup spool (52) are removed from the shaft assembly (34), adhesive is applied to the newly formed flat coils and the coils along with guides (28,30) are moved onto spindle (90) and against a flange (92). The guides (28,30) are removed from the shaft assembly (34) adjacent the newly wound coils stored against the flange (92) and remounted next to the winding device (42).

Abstract: The bobbin of an optical fiber canister is constructed so that the thermal expansion coefficient of the bobbin is matched to that of the optical fiber pack wound upon the bobbin. In one embodiment, an optical fiber canister (20) has a bobbin (22) in the shape of a frustoconical shell (24) with a flange (26) at one end of the shell (24), the bobbin (22) having a slot (34) through the shell (24) and the flange (26) extending longitudinally parallel to the axis (28) of the shell (24). In another embodiment, an optical fiber canister (50) has a bobbin (52) in the shape of a frustoconical shell (54) with a flange (56) at one end of the shell (54), the bobbin (52) being formed of at least two layers (62) of structural fiber (60) material helically wound and adhesively bonded into the shape of the shell (54). The structural fiber (60) material is selected to have substantially the same thermal expansion properties as optical fiber material, and may in fact be optical fiber.

Abstract: The RF/microwave switch/modulator uses an optically controlled diode 20. The reactance of the diode may be varied by varying the illumination intensity. In this fashion, the photodiode in conjunction with an external circuit can switch or modulate a microwave signal by varying the reactance of the diode using a laser light source or the like. The bias voltage may be varied to electronically tune the diode so that the microwave frequency of operation can be electronically controlled.

Abstract: A dispersion equalization technique for correcting dispersion-induced signal degradation within optical fibers is disclosed herein. The present invention prescribes a technique for synthesizing an optical fiber R of length L adapted to induce substantially zero dispersion at a wavelength W' included between first and second wavelengths W1 and W2. The optical fiber R includes first and second segments M and C of variable lengths L.sub.1 and L.sub.2 which induce substantially zero dispersion at the wavelengths W1 and W2, respectively.

Abstract: A fiber optic radar guided missile system 10 is disclosed which includes a radar receiver 12 disposed in a missile for receiving radar reflections and providing a first optical signal in response thereto. An optical receiver 14 is disposed at a launcher for receiving the first optical signal and for providing a set of electrical signals in response thereto. A fiber optic link 32 is connected between the missile and the launcher for communicating the first optical signal from the radar receiver 12 to the optical receiver 14.In a specific embodiment, the invention 10 includes a first system 12 disposed in a missile for receiving radar reflections which includes only an antenna 16 for receiving radar reflections, a radar seeker 18 for providing a first electrical in response to the received radar reflections, and a first fiber optic transmitter 26 for converting the first electrical signal into a first optical signal.