Detection of Microwave Orbital Angular Momentum by Azimuthal-Quadratic Phase Reflective Surface

A new method is proposed for detecting orbital angular momentum (OAM) in the microwave frequency band to address current detection challenges. Based on the principles of geometric coordinate transformation, this approach employs an azimuthal-quadratic phase reflective surface to achieve the conversion between OAM and focused electric field patterns at different azimuth coordinates on the receiving plane. This is the first application of an azimuthal-quadratic phase reflective surface in the detection of OAM in the microwave frequency band. To validate the proposed method, an azimuthal-quadratic phase reflective surface was designed, followed by a detailed analysis of its various parameters. Finally, the proposed method is verified through experiments. The results demonstrate good consistency between the simulated and measured outcomes.