Multi-objective optimization for UWB antennas in impedance matching, gain, and fidelity factor

A multi-objective optimizer is implemented to simultaneously cope with all the design requirements of ultra-wide band (UWB) antennas. The proposed method is based on the pixelated technique, which automatically achieves the design goals by means of Strength Pareto Evolutionary Algorithm 2 (SPEA2). In addition, a novel pixilated layout which exploits the current distribution more efficiently is proposed in this work. Our optimizer deals with the three performance criteria of UWB antennas: good impedance matching from 3.1 GHz to 10.6 GHz, constant gains in the broadside direction throughout the interested band, and little distortion between the time-domain transmitting and receiving signals. The capability of the proposed design technique is demonstrated by a compact UWB planar monopole design, and the optimized results show that the design goals are automatically achieved; therefore, the multi-objective optimization of UWB antennas can be accomplished in a more systematic way.