Reflection response control of bandwidth-enhanced antennas through constrained optimization

In this paper, we demonstrate the importance of precise reflection response control of enhanced-bandwidth antennas by means of automated simulation-driven optimization. In particular, a proper adjustment of antenna dimensions may lead to considerable broadening of the bandwidth even for small topological modifications of the structure. Computational efficiency of the design process is achieved by using surrogate-based optimization with coarse-discretization EM simulations utilized as the underlying low-fidelity antenna model. Furthermore, a penalty function approach allows us to precisely control the maximum in-band reflection so that sufficient margin to accommodate possible manufacturing tolerances is obtained. The optimized designs of the two antennas considered here feature over 31% and 38% bandwidth, respectively, w.r.t. the center frequency of 5.6 GHz. Simulation results are validated using measurements of the fabricated prototypes.