ANTENNA PULSE PATTERN SYNTHESIS IN A COMPLEX MEDIUM

WE PROPOSE TO STUDY TWO EFFECTS THAT RESULT FROM THE INTERACTION OF AN ELECTROMAGNETIC BEAM AND A MEDIUM WITH VARIABLE REFRACTIVE PROPERTIES. THE FIRST EFFECT IS THE BEAM SCATTERING THAT OCCURS BECAUSE THE INDEX OF REFRACTION IS A RANDOM FUNCTION OF POSITION AND TIME. THE SECOND EFFECT IS THE NONLINEAR INTERACTION THAT OCCURS WHEN A BEAM OF HIGH INTENSITY CAUSES THE MEDIUM TO LOCALLY CHANGE ITS INDEX OF REFRACTION. IN PHASE I THE TWO EFFECTS WILL BE STUDIED INDEPENDENTLY WHILE IN PHASE II THE MUTUAL INTERACTION WILL BE CONSIDERED. THE THEORY TO STUDY THE RANDOM SCATTERING IS WELL DEVELOPED FOR CW RADIATION. KNOWN RESULTS WILL BE SUMMARIZED TO SHOW HOW APERTURE DISTRIBUTIONS MAY BE SYNTHESIZED TO OVERCOME DEFOCUSING OF THE RADOM MEDIUM. RESEARCH WILL BE UNDETAKEN TO SHOW IF THE SAME TECHNIQUES CAN BE APPLIED TO FOCUS-WAVE PULSES. THE THEORY TO TREAT THE NONLINEAR INTERACTION IS STILL NOT TOO WELL DEVELOPED EXCEPT FOR VERY SIMPLE ASSUMPTIONS ABOUT THE INTERACTION. IN PHASE I WE SHALL SUMMARIZE THE CURRENT THEORY AND PRESENT CALCULATIONS FOR A SIMPLE TIME-INDEPENDENT INTERACTION. FINALLY, WE SHALL DETERMINE IF IT IS FEASIBLE TO DEVELOP A WORKABLE THEORY TO CONSIDER THE TIME-DEPENDENT INTERACTION.