Efficiency and Accuracy of Computer Simulations of the Input Impedance of Wide-Band Antennas

A converging impedance simulation of multi-octave microwave radar antennas typically requires 4-12 hours of processor time on a 700 MHz Pentium platform. Inside the simulation environment the obtained results, e.g. SWR, provide a useful tool for optimization and tuning and show the desirable direction of modifications but for the selected test case the real measured values deviate often by 50 per cent from the calculated ones. Most implemented adaptive curve-fitting schemes seem to fail on the Smith chart due to the cyclic nature of the response. Thus only a small enough frequency step will improve accuracy whereby the computation time is further increased.