Exploiting advanced composite materials for lightweight shipboardSHF satellite communication antennas

摘要

Naval satellite communications and capacity requirements demandnimproved shipboard antenna performance. Extraordinary design featuresnand the use of lightweight composite materials are necessary to meet thenrequirements of a shipboard antenna for SHF satellite communications.nAdvanced materials, modeling, and analysis techniques are used tonproduce high-efficiency antennas for operating in shipboardnenvironments. The major requirements for the antenna are discussed.nThese are achieved using advanced technology in materials and design.nSize and weight reductions are achieved using a gimbal structurenemploying advanced composite materials for the primary structuralncomponents. Lightweight composites in combination with stainless steelnbrackets provide the strength and stiffness required for a shipboardnenvironment. Three axes support dynamic platform motion while reducingnmotor drive torque requirements. High gain and low noise temperature arenachieved by an extremely high-efficiency Cassegrain antenna with lownside and back lobes. Integration of redundant LNAs as part of thenelevation housing reduces losses between the orthomode transducer (OMT)nand LNA input. The orthomode transducer is a well-matched three-portnwaveguide junction. Orthogonal modes entering the common port of thentransducer exit in individual, rectangular waveguides, one for thenreceive band and the other for the transmit band. By substantiallynreducing these losses, the antenna can achieve an impressive G/T rationof 19.0 dB/° K. A complete description of the antenna, its design,nand performance are described