Millimeter-Wave High-Aperture-Efficiency Conformal Impedance Metasurface for OAM Generation Using Blackman Function Optimization Algorithm

In this paper, a low-profile, high aperture efficiency (AE), and high orbital angular momentum (OAM) purity conformal Impedance metasurface (CIMS) is proposed. The modulation depth is optimized using the Blackman function (BMF) to achieve the advantages of high AE and OAM purity. To verify the optimization effect of the BMF, two CIMS are designed, one using the BMF to optimize the modulation depth, and the other one without any optimization. Through the comparison of the simulation results of the two CIMS, it can be concluded that the CIMS optimized with BMF has the higher AE of 14.8%, the gain of 18.8dBi, and the OAM purity of 92.5%. The simulation and experimental results are in good agreement with the theoretical analysis. The results show that the CIMS optimized with BMF has the advantages of high AE, low profile, and high OAM purity, and provide a reference for OAM communication and vortex radar with conformal devices.