Design Optimization of Metasurface Filter Integrated With Base Station Antenna for Sub-6 GHz 5G Communications

This paper proposes a metasurface filter integrated with a base station antenna for sub-6 GHz 5G communications. The metasurface filter, composed of a pixel-based geometric structure, is optimized using the conformational space annealing (CSA) algorithm. The proposed metasurface filter exhibits bandpass characteristics around the 3.5 GHz frequency, commonly used in sub-6 GHz 5G networks. The performance of the metasurface filter combined with a 4x1 patch antenna array was measured in a fully anechoic chamber. The measured gain pattern shows that the metasurface filter passes the signal with a small insertion loss in the passband and effectively suppresses out-of-band frequencies, providing frequency-selective performance.