Abstract: A dual band radiating element and modular antenna array suitable for application in space communications is provided. The dual band radiating element comprises a stacked patch antenna for transmitting RF signal of a first signal frequency band (e.g. S-Band) and receiving RF signals of a second signal frequency band (e.g. L-Band). The concentric design of the radiating element can achieve savings in material and mass compared to other stacked patch antennas. For effective operation in space applications, a first radiation patch in the radiating element is isolated from a second radiation patch by shielding a feed pin to the first radiation patch as it travels through the dielectric layer separating the patches. Individual radiating elements can be attached to individual filter/amplification units in a modular antenna array allowing for individual components to be easily installed, repaired or replaced with minimal impact to the rest of the antenna array and/or spacecraft.

Abstract: A steerable antenna architecture, or configuration, for optimal steering of transmitting and/or receiving beam over wide scan angles, is capable of steering the beam on a full hemisphere (2? steradians), with no singularity or key-hole within a coverage area and with only one RF rotary joint. The architecture includes a dual-reflector assembly defining an antenna focal point located close to a main reflector surface and a signal feed chain having a signal source located adjacent to the antenna focal point and defining a feed axis substantially pointing towards a sub-reflector intersection point. A first actuator rotates the feed chain and the dual-reflector assembly about a first rotation axis generally perpendicular to the feed axis and not intersecting with the coverage area. A second actuator rotates one of the main reflector and the dual-reflector assembly about a second rotation axis aligned with the feed axis.

Abstract: A steerable antenna architecture, or configuration, for optimal steering of transmitting and/or receiving beam over wide scan angles, is capable of steering the beam on a full hemisphere (2 ? steradians), with no singularity or key-hole within a coverage area and with only one RF rotary joint. The architecture includes a dual-reflector assembly defining an antenna focal point located close to a main reflector surface and a signal feed chain having a signal source located adjacent to the antenna focal point and defining a feed axis substantially pointing towards a sub-reflector intersection point. A first actuator rotates the feed chain and the dual-reflector assembly about a first rotation axis generally perpendicular to the feed axis and not intersecting with the coverage area. A second actuator rotates one of the main reflector and the dual-reflector assembly about a second rotation axis aligned with the feed axis.

Abstract: In method of controlling an optical amplifier dynamically adapts to both configuration and performance changes of a communications system. An error vector is calculated to indicate a difference between respective detected values and target values of a parameter of a light beam downstream of the optical amplifier. A sensitivity matrix indicative of a sensitivity of the detected parameter value to incremental changes in a control variable of the optical amplifier is calculated. A predicted optimum value of the control variable is then calculated using the error vector and the sensitivity matrix. Calculation of the predicted optimum control variable value can be iterative, with the sensitivity matrix calculated either during each iteration, or at the beginning of each optimization run. As a result, optimization of the amplifier control variables is performed based on a sensitivity matrix that accurately reflects the performance of the amplifier.