Enhancing radiation response of ultrawideband monopoles using surrogate-based optimization

Both radiation and reflection responses of ultrawideband (UWB) antennas are frequency dependent in general. Adjustment of geometry and material parameters of UWB antennas for a required impedance bandwidth has been extensively addressed in publications. Additional improvement of certain radiation figures of the UWB antennas is a more demanding problem which can be handled using simulation-based numerical optimization. In this work, we use the surrogate-based optimization approach to enhance the realized gain response of the conical monopole configuration over the UWB bandwidth by making the response more uniform in both frequency and elevation angle (within the considered elevation sector). Our approach is illustrated using the example of the UWB monopole. We demonstrate that a substantial enhancement of the radiation response without degradation of matching can be achieved at a numerical cost of only a few high-fidelity simulations of the antenna structure under study.