SCATTERING PROBLEMS OF ELECTROMAGNETIC WAVES

THE DEVELOPMENT OF AN EFFICIENT NUMERICAL ALGORITHM (COMPUTER CODE) CAPABLE OF DETERMINING THE UNKNOWN MATERIAL COMPOSITION AND SHAPE OF AN ARBITRARY TARGET FROM THE MEASURED ELECTROMAGNETIC WAVES IN THE FAR FIELD REGION WILL ENHANCE THE CAPABILITY OF THE DEFENSE RADAR SYS-TEM TO DEFEAT KNOWN EVASIVE SCHEMES. THIS CAN BE ACHIEVED BY IMPROVING THE PROVEN ITERATIVE NUMERICAL ALGORITHM, GENERALIZED PULSESPECTRUM TECHNIQUE (GPST), BY TAKING ADVANTAGES OF PARALLELISM, VECTORIZATION, ADAPTIVE GRIDS, DOMAIN DECOMPOSITION, ETC. THE PHASE I EFFORT IS TO DEVELOP AN EFFICIENT COMPUTER CODE FOR CALCULATING THE TIME-HARMONIC ELECTROMAGNETIC WAVES SCATTERED FROM A TWO-DIMENSIONAL SCATTERER OF ARBITRARY MATERIAL COMPOSITION AND SHAPE. THIS COMPUTER CODE IS AN IMPORTANT SUBROUTINE OF GPST FOR SOLVING THE INVERSE SCATTERING PROBLEMS, AND IT CAN BE 30 TIMES FASTER THAN THE EXISTING FINITE DIFFERENCE TIME-DOMAIN METHOD (WITH THE SAME ACCURACY) BY THE ESTIMATION OF THE TOTAL FLOATING POINT ARITHMETIC OPERATION COUNT NEEDED FOR THE CALCULATION.