ADAPTIVE NULLING BY ELECTRICAL SURFACE CONTROL OF A REFLECTOR ANTENNA

AN INNOVATIVE APPROACH TO FORMING A NULL IN THE SECONDARY PATTERN OF A REFLECTOR ANTENNA IS DEVELOPED BY THIS PROJECT. AN ELECTRONICALLY CONTROLLABLE REFLECTIVE SURFACE BEING DEVELOPED ON A NASA SBIR IS THE STARTING POINT FOR THE WORK. THIS PROJECT EXTENDS THE PERFORMANCE OF THE SURFACE SO THAT IT IS USEFUL AS A NULL FORMER. THE RESULT IS CONSIDERABLY REDUCED COST OF NULL STEERING ANTENNAS. THE DEVICE FORMS PART OR ALL OF THE ANTENNA'S MAIN REFLECTOR OR ITS SUBREFLECTOR. THE REFLECTIVE PHASE (AND AMPLITUDE IF REQUIRED) OF EACH SMALL PORTION OF THE UNIQUE SURFACE IS CONTROLLABLE SO THAT THE TOTAL PATTERN REFLECTED OFF THE SURFACE IS CONTROLLABLE. IN THIS PROJECT, THE USE OF THIS DEVICE TO FORM ANTENNA NULLS IS EXPLORED. THE NECESSARY DESIGN IMPROVEMENTS TO THE BASIC NASA SURFACE ARE DEVELOPED AND TOTAL ANTENNA PERFORMANCE USING THE DEVICE AS A NULL STEERER IS PREDICTED. PHASE 2 OF THIS PROJECT WILL VERIFY NULLING PERFORMANCE BY MEASUREMENTS.