An array-fed reconfigurable reflector for flexible coverage

The paper describes a new type of reconfigurable reflector antenna for spacecraft applications in which both the reflector shape and the excitation of a small array feed combine to offer maximum coverage flexibility. To create a reconfigurable continental coverage the array is excited to produce a suitably tapered circularly symmetric pattern and the shape of the mesh reflector adjusted to yield the appropriate secondary radiation pattern. When spot beams are required within the coverage region, the mesh reflector is configured as a paraboloid and individual elements or local clusters excited within the array. The results of a theoretical study are described which involve a representative 50¿ reflector. For purpose of comparison between experiment and theory the QMW mesh reflector is used and this is of 28.5¿ diameter at the centre operating frequency of 1OGHz. The antenna is fed from a 19 element array of small dominant-mode conical horns.