Efficient Spline-Based Antenna Miniaturization via Heterogeneous Multiobjective Optimization

This letter proposes a spline-based wideband antenna. Compared to fixed-shape antennas, the proposed spline-based antenna allows shape adjustment through parameters, thus improving design flexibility. The antenna miniaturization problem consists of both computationally expensive and cheap design objectives. Specifically, the expensive and cheap objectives are simulated reflection coefficient and calculated antenna area, respectively. Although the antenna miniaturization problem can be solved by current expensive multiobjective optimization algorithms, these algorithms usually assume that all objectives are computationally expensive and should be approximated by Kriging models in optimization. This assumption neglects the fact that cheap objectives can be computed quickly and accurately by direct evaluation of the exact functions. Therefore, to further improve optimization efficiency, a Kriging-based efficient global optimization algorithm is proposed by introducing two direct evaluation strategies for cheap objectives. These strategies are based on a pseudo-heterogeneous improvement matrix infill criterion. Therefore, the antenna miniaturization problem can be effectively solved by the spline-based antenna design method and the proposed algorithm. Results indicate that the proposed algorithm is more efficient than all compared algorithms.