ARRAY-FED RECONFIGURABLE REFLECTOR FOR SPACECRAFT APPLICATIONS

The paper describes a new type of reconfigurable reflector antenna for spacecraft applications, in which both the reflector shape and the ex citation of a small array feed combine to offer maximum coverage flexi bility. To create a reconfigurable continental coverage, the array is excited to produce a suitably tapered, circularly symmetric pattern, a nd the shape of the mesh reflector adjusted to yield the appropriate s econdary radiation pattern. When spot beams are required within the co verage region, the mesh reflector is configured as a paraboloid, and i ndividual elements or local clusters excited within the array. The res ults of a theoretical study are described which involve a representati ve 50 lambda reflector. The comparison between experiment and theory i s made using a prototype mesh reflector, whose performance with a sing le feed has been previously described, and whose centre operating freq uency is 10 GHz. The antenna is fed from a 19-element array of small d ominant-mode conical horns. Generally, excellent agreement between the oretical predictions and experimental results is obtained.