A circularly polarized phased array antenna system for both reception and transmission applications includes a plurality of planar radiating (or receiving) elements, a switching matrix for each radiating element, a beamforming network and a transmit/receive module. Each planar element includes 4×N radially disposed segments that may be selectively connected with the four modes of a circularly polarized signal such that two opposing segments function as the two respective arms of a dipole radiating element and two orthogonal such dipoles function as a crossed pair of dipoles for receiving or transmitting the circularly polarized signal. The switching matrix and the beamforming network cooperate to determine the polarization phase of the radiating element by commutating the four modes of the circularly polarized signal to any four orthogonal segments of the radiating element. The polarization sense may be changed between right-hand and left-hand circular either within the bandforming network, or by causing the switching network to reverse the two signal modes connected across one of the dipoles. If N is greater than 1, then by electrically connecting up to N-1 nearby segments to thereby increase the effective angle subtended by each arm, the bandwidth may be increased while still permitting the radiating element's polarization phase to be determined in increments equal to the angle subtended by one segment; by selectively using either an odd or even number of segments to define the effective angle subtended by each dipole arm, the relative phase of that element may be determined in increments equal to half the angle subtended by one segment.

Phased array antenna system using polarization phase shifting

Dust caps for use with multiple optical fiber adapters and connectors. A first embodiment of the invention is a dust cap for use with ST adapters, ST connectors and SC connectors. The dust cap includes a sealing surface for contacting the bottom of an ST adapter for sealing the portion of the adapter containing the alignment sleeve. The dust cap also includes an opening having a reduced diameter to prevent contamination of the tip of the ferrule of an ST or SC connector. The dust cap may be formed in a duplex fashion and include a retaining strap for securing the dust cap to an ST adapter. An alternative embodiment of the invention is a dust cap having a first side for mating with either an SC or ST adapter and a second side for mating with either an SC or ST connector.

Dust caps for use with telecommunications adapters and connectors

A shield for the end of a fiber optic connector or fiber optic connector adapter is disclosed. The shield includes a radiation absorbing element which prevents significant amounts of potentially harmful electromagnetic radiation from being discharged through the end of a connector or adapter.

Radiation absorbing shield for fiber optic systems

A conical corrugated microwave feed horn (10). A conical flare section (60) is formed at the aperture (20) of the feed horn (10) and a second smooth cylindrical section (200, 210) is formed at the throat (30) of the feed horn (10). The conical flare section (60) is formed with two regions (70, 220) whereby region (70) is a corrugated conical region formed at the aperture (20) and having a plurality of slots (70) formed parallel to the central axis (204) of the feed horn (10). Each slot (70) in the plurality of slots (70) has an inner surface (250) closest to the central axis (204) of the feed horn and an outer surface (240) furthest from the central axis (204). The first slot (70A) adjacent the smooth conical region (220) has first and second formed lips (280, 290) on the terminating end. The last slot (70C) of the plurality of slots (70) at the aperture (20) of the feed horn (10) has the terminating end of the inner surface (240B) extending in length beyond the length of the outer surface (240C).

Conical Corrugated Microwave Feed Horn

A duplex optical fiber connector (20) includes a housing (21) having a cable entrance end and a plug end. At the cable entrance end, an optical fiber cable (23) which includes two individually buffered optical fibers (25--25), strength member yarn (29) and a plastic jacket is routed into a flanged end of a bushing (45) having a tapered passageway therethrough. The bushing is supported in a base (22) of the housing. The jacket is removed from the portion of the cable which extends from the cable entrance end to the plug end and the yarn is positioned between two conformable, truncated conically shaped, substantially smooth surfaces which define the passageway of the bushing and a truncated conically shaped wedge (50) which is received in the passageway. The wedge includes a bore through which the optical fibers extend. This locking arrangement in which the yarn makes no retroflexed turns is self-enhancing when tensile forces are applied to the cable. At the plug end are secured two plugs (70--70) each terminating one of the optical fibers. Each plug is spring-loaded and further, end portions of the plugs which protrude beyond the connector housing are protected by a bumper (90) which also is spring-loaded and which is moved inwardly when the connector is assembled to another. A cover (52) is assembled to the base to complete the housing and to secure the force-transfer facilities and plugs therein.

Duplex optical fiber connector

A flexible flap, having an elastic memory, which flap is used to normally cover a lightwave connector so as to prevent laser radiation emissions from the connector. The flexible nature of the flap allows the forcible deflection thereof, so that a mating connector can be attached to the normally covered one, and yet when the mating connector is removed the flap will automatically return to the covering position. In addition to preventing the emission of laser radiations, the flap can reduce contamination materials, such as dust, from covering the end of the fiber optic material.

Fiber optic connector cover apparatus

A corrugated feed horn and its method of manufacture is disclosed for circularly polarized SHF (super high frequency) and EHF (extra high frequency) parabolic antennas operating in the 12-100 GHz range. A plurality of laminations are dip braze bonded, providing alternate fins and grooves in an inner conical configuration. Extremely thin fins are enabled without expensive parts or fabrication methods.

Dip brazed corrugated feed horn

A flush-mounted radiating antenna is disclosed which can be electronically switched to produce a rotating directional field with no moving parts in the antenna element itself or with the appropriate electronics in the entire mechanism. This is accomplished by utilizing pie-shaped sections on the flush surface which are capacitively coupled to a central feed element and shorting some of the pie-shaped capacitively coupled elements to a ground plane whereby the normally omnidirectional pattern is perturbed to a directional pattern.

Flush mounted tacan base station antenna apparatus

A radio navigation antenna system suitable for use in an aircraft is disclosed. The fed element of the system is stationary, being at one end of a coaxial conductor which extends through a hollow shaft of a motor. Mounted around the hollow shaft is a ground plane disc capacitively coupled to the outer sleeve of the coaxial conductor, thereby avoiding the use of brushes in the system. A cylindrical dielectric antenna support is mounted on the ground plane disc around the fed element. A T-shaped reflector is formed by a conductive layer on the cylindrical surface of the antenna support.

Theodore A. Dumas

Papers

Fiber optic connector cover apparatus

Dip brazed corrugated feed horn

Flush mounted tacan base station antenna apparatus

Radio navigation antenna system for aircraft