Technology challenges and trade-offs in application of multiple-beam antennas to NASA´s Personal Access Satellite System

The authors discuss the trade-offs and technology challenges that exist in developing the multiple-beam satellite antennas for Personal Access Satellite System (PASS), and address the different techniques that can be used to meet some of these challenges. More specifically, they look at different types of multiple-beam antenna systems that can provide full coverage of the contiguous United States such as fixed beam, switched beam, or scanned beam systems. They also discuss some techniques for inter-beam power management for efficient use of satellite power and reliable operation. In this area, two different adaptive schemes are discussed. One is the multiple-port hybrid transponder, where each beam is generated by separate feed array elements of the satellite reflector antenna. The other is a full array beam-forming network, where each beam is generated by all the feed array elements. Other major challenges that need to be addressed for the successful development of PASS are discussed briefly.<>