Multi-mode antenna optimization

It is pointed out that one can anticipate that successful advanced antenna concepts will comprise a blend of new BFN and antenna technologies and improved antenna synthesis approaches. The multibeam reflector antenna design and synthesis software aspect is addressed. It is noted that the requirements of simple feed networks and high antenna performance are in conflict. If the footprint size of an antenna system matches the coverage area specifications, multimode antenna concepts may be applied to implement multifunction antennas with only limited performance losses compared to single-function antennas. SubBFN techniques are useful in reducing the complexity of the feed network. The introduction of small additional losses in the feed network, 0.1 to 0.2 dB, to implement feed distributions that are not fully orthogonal is a promising future development. The multimode antenna concepts may be combined with reconfigurable antenna concepts to make more simultaneous beam ports available and minimize the switching requirements in the feed network. This will allow a flexible allocation of the transponders to the different beams.<>