Retrodirective antenna array

Claim 1

ELECTROMAGNETIC ENERGY ANTENNA MEANS COMPRISING THE COMBINATION OF A REFERENCE ANTENNA ELEMENT AND A PLURALITY OF SECONDARY ANTENNA ELEMENTS SPACED FROM EACH OTHER AND SAID REFERENCE ELEMENT, EACH OF SAID ELEMENTS BEING POSITIONED TO RECEIVE ENERGY FROM THE ELECTROMAGNETIC SOURCE AND PRODUCE A MICROWAVE SIGNAL IN RESPONSE THERETO, A VARIABLE PHASE SHIFTING MEANS OPERATIVELY INTERCONNECTED WITH EACH OF SAID SECONDARY ELEMENTS, EACH OF SAID PHASE SHIFTING MEANS INCLUDING A CONTROL INPUT AND MEANS FOR VARYING THE PHASE OF SAID MICROWAVE SIGNALS PASSING THROUGH IN PROPORTION TO THE AMPLITUDE OF A CONTROL SIGNAL APPLIED TO SAID INPUT, PHASE COMPARING MEANS OPERATIVELY INTERCONNECTED WITH AT LEAST ONE OF SAID PHASE SHIFTING MEANS AND BEING RESPONSIVE TO THE SIGNAL FROM SAID REFERENCE ELEMENT AND THE SIGNAL FROM THE SECONDARY ELEMENTS CORRESPONDING TO THE LAST MENTIONED PHASE SHIFTING MEANS TO PROVIDE A CONTROL SIGNAL THAT IS A FUNCTION OF THE DIFFERENCE BETWEEN THE PHASES OF THE MICROWAVE SIGNALS ON SAID ELEMENTS.