Electronically adaptive antenna systems

Electronically adaptive receiving and transmitting antenna systems which can be employed for ground tracking stations and satellite and space vehicles are discussed. The receiving antenna systems described herein contain active elements which, unlike in passive antenna arrays, automatically adjust the electrical phases of the signals received by the array elements to obtain antenna directivity. The self-focusing feature of these receiving antenna systems is achieved by a set of phase-locked loops, which permit phase adjustments of signals received by various antenna elements continuously regardless of the direction of the transmitting source. For a transmitting antenna, the self-focusing feature is provided by a pilot signal from the receiving station which enables the transmitting antenna beam to point in the direction of the receiving station automatically. The basic principles of operation of active adaptive receiving and transmitting antenna arrangements, including performance analyses in the presence of noise, are presented in this paper to demonstrate the usefulness of such antennas.