High-Efficiency and Ultrawideband Polarization Conversion Metasurface Based on Topology and Shape Optimizaiton Design Method

This study introduces a two-stage optimization method for designing an ultrawideband polarization conversion metasurface. By integrating topology and shape optimization techniques, the proposed method expands the design space to achieve enhanced polarization conversion bandwidth. The first stage employs genetic-algorithm-based topology optimization to establish the initial structural configuration through binary coding. Subsequently, the second stage refines the design through shape optimization by extracting and modifying the boundaries of the topology-optimized structure. The optimized design demonstrates high polarization conversion efficiency (>90%) across 4.08–14.39 GHz, yielding a relative bandwidth of 111.64%, which represents a 4.88% improvement compared to topology-only optimization. This enhancement demonstrates the effectiveness of our combined optimization method in ultrawideband polarization conversion metasurface design, offering a promising method for developing high-performance electromagnetic devices.