A self-steering array repeater

A scheme is disclosed whereby an antenna array is automatically directed by a simple intermodulation of signal components. In reception, each array element feeds a pilot signal and the modulated signal to a third-order mixer wherein the phase associated with the signal in that element is automatically cancelled. This allows in-phase addition of the contributions from the many elements irrespective of the array shape or the direction of the incoming signal. For transmission, a pilot signal received from the distant receiver location provides by intermodulation a phase compensation to the signal radiated from each transmitting element so as to automatically direct the radiated signal to the distant receiver. There are no significant restrictions as to the shape of the array or the frequencies used. The scheme lends itself to multiple-element, low-power circuitry and may be used in either space or terrestrial systems to give a high repeater directivity without requiring stabilized platforms or control of antenna orientation. An experimental verification of the basic principle is described