A scalar–tensor impedance metasurface for frequency‐multiplexed multifunctional orbital angular momentum beams generation

A scalar‐tensor composite holographic impedance meta surface (HIMS) for frequency‐multiplexed is proposed. The scalar and tensor parts operate at low frequency and high frequency, respectively, the coupling between them can be over come, and then more multifunction orbital angular momentum (OAM) beams with good performance can be obtained. As an example, a scalar‐tensor HIMS is designed for three OAM beams: (1) Beam‐I at fL = 11.2 GHz, which is generated by scalar part. (2) At fH = 18.2 GHz, Beam‐II and Beam‐III, which are generated by tensor part. The proposed scalar‐tensor HIMS has the following advantages: (i) More flexible multifunction design due to the decoupling of scalar and tensor parts. (ii) High aperture efficiency (14.93% at 11.2 GHz, much higher than conventional scalar HIMS, 23.3% at 18.2 GHz). The HIMS can be used in future high‐capacity secure communication, imaging, and so on.