Frequency-domain and time-domain performance enhancements of ultra-wideband antennas using multiobjective optimization techniques

Two multiobjective optimization techniques for ultra-wideband (UWB) antenna design are presented. While most of the optimization methods for UWB antenna design cope with only the impedance characteristics, the proposed techniques handle all the frequency-domain and time-domain design goals, including wide impedance bandwidth, constant gain variation, and high fidelity factors, thereby leading to an efficient and systematic way for UWB antenna development. The first technique is based on size optimization, using fractional factorial designs (FFDs) to build the response surface model for each design goal. The second technique is based on topology optimization, using strength Pareto evolutionary algorithm 2 (SPEA2) to obtain the optimum pixelated layout. The two multiobjective optimization methods are respectively applied to the design problem of UWB planar monopole antennas. Both techniques exhibit excellent performances, and all the design tasks are successfully achieved.