Optimization of a resistively-loaded horn for mine detection

Five basic versions of an U.S. Army Research Laboratory (ARL) built Synchronous Impulse Reconstruction (SIRE) radar antenna were modeled using the method of moments (MOM) algorithm in FEKO computational electromagnetics software with the goal of improving the antenna performance. The antennas consist of two-sided, open horns where horizontal, resistively loaded parallel plates were attached at the radiating end of the horn. Three of the models featured cylindrical flares attached to the end of the parallel plates. Each of the five versions was optimized over a small range of geometry and resistance parameters. The computations predicted that the design using resistive sheets in the parallel line structure with no flare had the best performance because of its combination of favorably low S11 parameters and forward-directed vertical electric far field.