Software tools for efficient generation, modelling and optimisation of fractal radiating structures

This study describes in-house developed software tools for designing micro-strip patch fractal antennas. As the fractal geometry is quite complex, IFSMaker application was developed purposely for an easy definition and maintaining of planar fractal structures. In the next step, the authors use the cavity model technique for modal analysis of internal fields of the patch. This simplified model is reasonably fast, so that the optimisation loop may be employed in order to reduce the fundamental mode resonant frequency. This is accomplished with the EvalInFEM, PSOoptimizer and IFSLimiter applications. The theory of characteristic modes is then used to refine the results and finally the antenna is simulated with a full-wave CST simulator, built and measured.