RCS PREDICTION USING FREQUENCY DEPENDENT FINITE DIFFERENCE TIME DOMAIN (FDFDTD) METHOD

RECENT ADVANCES INDICATE THAT TIME DOMAIN CALCULATIONS BASED ON FINITE DIFFERENCE (FDTD) HAVE THE CAPABILITY TO ACCURATELY COMPUTE RCS FROM GEOMETRICALLY GENERAL VEHICLES COMPOSED OF NONHOMOGENOUS MATERIALS. THE FDTD METHOD INVOLVES DIVIDING THE VEHICLE INTO SMALL CELLS. THE MATERIAL IN EACH CELL MAY BE SPECIFIED INDEPENDENTLY, THUS ALLOWING THE GREAT FLEXIBILITY. AN INCIDENT PLANE WAVE IS SPECIFIED ANALYTICALLY, AND THE PROGRESS OF THE INCIDENT WAVE AND ITS INTERACTIONS WITH THE VEHICLE ARE COMPUTED AT SMALL TIME STEPS. SEVERAL FOUNDAMENTAL EXTENSIONS TO THE FDTD METHOD HAVE GREATLY EXTENDED ITS APPLICABILITY. THESE EXTENSIONS INCLUDE THE CAPABILITY TO MODEL FREQUENCY DEPENDENT DISPERSIVE MATERIALS, AND TO TRANSFORM THE NEAR ZONE FIELDS TO THE FAR ZONE IN THE TIME DOMAIN IN ORDER TO ALLOW WIDEBAND COMPUTATION OF RCS. THE PROPOSED DEVELOPMENT SHOULD ALLOW COMPUTATION OF RCS WITH VIRTUALLY ANY MATERIAL AND GEOMETRY, SUBJECT ONLY TO COMPUTER RESOURCE LIMITATIONS.