Abstract: A device and method are described for duplex satellite communication over a single satellite antenna. A satellite ground terminal may utilize a frequency-selective surface module including a frequency-selective surface as a subreflector acting as a frequency diplexer to separate signals received and/or transmitted by a first feed and a second feed of a satellite ground terminal, where each feed has a separate antenna horn. The frequency-selective surface module may be used in combination with a second subreflector such that a first feed and a second feed of the satellite ground terminal are implemented on the same side of the frequency-selective surface module.

Abstract: An antenna system comprises an antenna feed support and a driver. The antenna feed support is configured to mount a circularly polarized antenna feed to an antenna dish to extend outward along a longitudinal axis of the circularly polarized antenna feed with respect to a reflective surface of the antenna dish. The driver is configured to rotate the circularly polarized antenna feed to adjust alignment between the circularly polarized antenna feed and a remote antenna. The driver can rotate the circularly polarized antenna feed mechanically, electrically or both to adjust alignment between the circularly polarized antenna feed and a remote antenna to reduce cross-pol discrimination at the circularly polarized antenna feed.

Abstract: Systems and methods are provided for separating the uplink signal from the downlink signal in a satellite communication system. A communication terminal for satellite communications is provided, comprising a reflector having a prime focus; a first feed located at the prime focus of the reflector and in optical communication with the reflector; a frequency-selective surface module having a reflected focus and located at a point along a communication path between the main reflector and the first feed; and a second feed located at the reflected focus of the frequency-selective surface module and in optical communication with the frequency-selective surface module.

Abstract: An integrated waveguide for use in high radio frequency communication is provided. The integrated waveguide including: a first substrate including a first plastic layer having on a first inward-facing surface, a first portion of a waveguide feature formed on the first inward-facing surface, and a metal layer disposed on the first inward-facing surface; and a second substrate including a second plastic layer having a second inward-facing surface, a second portion of a waveguide feature formed on the second inward-facing surface, and a metal layer disposed on the second inward-facing surface, wherein the first substrate and the second substrate are assembled to define an integrated waveguide feature defined by an assembling of the first portion of the waveguide feature and the second portion of the waveguide feature.

Abstract: A radio is provided for transmit-receive isolation and filtering (INTRIFWA) that are sealed and/or integrally built-in a housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems.

Abstract: An radio is provided for transmit-receive isolation filtering and circular polarization (INTRIFPWA) that are sealed within a metal housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems.

Abstract: An radio is provided for transmit-receive isolation filtering and circular polarization (INTRIFPWA) that are sealed within a metal housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems.

Abstract: A radio is provided for transmit-receive isolation and filtering (INTRIFWA) that are sealed and/or integrally built-in a housing of a transmitter, which can be used in microwave communication systems, including satellite based communications systems and terrestrial based microwave communication systems.

Abstract: Treated port fuel injectors are disclosed. The treated port fuel injectors have a surface coated with a film which resists or limits deposit formation on the injector surface. The film may be formed by contacting the port fuel injector with: (i) a succinimide compound comprising the reaction product of polyisobutylene-substituted succinic anhydride and a polyamine; (ii) a Mannich base detergent; and (iii) a spark ignition fuel. The treated port fuel injectors may also include a film formed by contacting the port fuel injector with: (i) a Mannich condensation reaction product of a polyamine having a sterically-hindered primary amino group, a hydrocarbyl-substituted hydroxyaromatic compound, and an aldehyde; and (ii) a spark ignition fuel. Methods of forming films on port fuel injector surfaces are also disclosed.

Abstract: New, highly effective Mannich detergents for use in hydrocarbon fuels are described which reduce engine deposits in spark and compression ignition internal combustion engines. They are Mannich condensation reaction products obtained from reacting: (i) a polyamine having a sterically-hindered primary amino group, (ii) a hydrocarbyl-substituted hydroxyaromatic compound, and (iii) an aldehyde. These Mannich detergent compounds may be dispersed in a liquid carrier to provide a fuel additive concentrate for hydrocarbon engine fuels which effectively control engine deposit formation in intake valves and also other engine regions such as port fuel injectors and combustion chambers.

Abstract: There is disclosed a Mannich reaction product and a reaction to create a Mannich reaction product prepared from an amino alcohol, a high molecular, weight hydroxy aromatic compound, and an aldehyde. Compositions comprising a hydrocarbon fuel and the reaction product are also disclosed.

Abstract: A method of pointing an antenna at a transmitter comprising the steps of: (a) varying the azimuth of the antenna dish a predetermined number of degrees in a first direction from a predetermined azimuth angle; (b) measuring a first signal strength of an incoming signal received by the antenna dish; (c) varying the azimuth of the antenna dish the same predetermined number of degrees in a second direction from the predetermined azimuth angle, where the second direction is opposite to the first direction; (d) measuring a second signal strength of the incoming signal received by the antenna dish; and (e) comparing the first signal strength to the second signal strength, and if the first signal strength substantially equals the second signal strength, the current predetermined azimuth angle represents the optimal angle of azimuth for the antenna dish.

Abstract: An approach for providing a multiple-beam antenna system for receiving and transmitting electromagnetic signals from a plurality of closely spaced satellites is disclosed. Dielectric inserts are selectively coupled to the feedhorn bodies to alter the radiation patterns according to dielectric constants of the dielectric inserts. A reflector produces multiple antenna beams based upon the altered radiation patterns of the feedhorn bodies. The antenna provides simultaneous transmissions to satellites that are spaced about 2° or less.

Abstract: An RF emission hazard zone of an RF transceiver is controlled to ensure that RF energy density limits for humans is not exceeded when a human body part enters the RF hazard zone near an antenna reflector and feedhorn. In a first aspect, a transmitter duty cycle is reduced to effectively reduce the average power transmitted from the antenna whenever a signal level of a received signal is reduced below a threshold value. The reduction in average transmitter power reduces the RF emission hazard zone near the antenna, and limits the exposure of any person who has intruded into the hazard zone. In a second aspect, the transmitter is disabled whenever a received signal is affected so that signal quality, bit-energy-to-noise ratio (Eb/No), synchronized state in a demodulator, lock condition in a FLL, or received signal strength are degraded, indicating that a human has intruded into the RF hazard zone.

Abstract: An approach for providing a multiple-beam antenna system for receiving and transmitting electromagnetic signals from a plurality of closely spaced satellites is disclosed. Dielectric inserts are selectively coupled to the feedhorn bodies to alter the radiation patterns according to dielectric constants of the dielectric inserts. A reflector produces multiple antenna beams based upon the altered radiation patterns of the feedhorn bodies. The antenna provides simultaneous transmissions to satellites that are spaced about 2° or less.