Study of the performance and limitations of multiple-beam antennas. Part 1: Study, design, construction and evaluation of a multiple-beam antenna

The electrical performance and limitations of multiple-beam antennas for spacecraft applications were studied. A survey of the antenna types which offer a potential means of satisfying a general multiple-beam specification proposed by the European Space Agency was made. A recommendation for a 'preferred' antenna configuration comprising an offset parabolic reflector used in conjunction with a multiple-element primary-feed is given. Based upon this recommendation, a design procedure was established for circularly polarized offset reflector antennas (described in detail in Part 2 of the report). The design procedure was applied to an ESA specification for a multiple-beam antenna with 3 closely-spaced beams. The design, construction and experimental evaluation of a breadboard antenna is described. Finally, conclusions are drawn and recommendations made for future work in this technical area.