Variable Scale Aperture Sampling Reception Method for Multiple Orbital Angular Momentum Modes Vortex Wave

In this paper, we propose a kind of variable scale aperture sampling reception (VSASR) method for multiple orbital angular momentum (OAM) modes vortex wave reception and demodulation. The VSASR method overcomes the restrictions of equal interval OAM modes which is necessary for the existing partial aperture sampling reception method for keeping the OAM modes orthogonality. Thus, it has higher OAM modes multiplexing utilization efficiency than the partial aperture sampling reception method at the same reception aperture. It is also well for vortex wave consistency reception. Although the orthogonality is a little damaged and there are some other crosstalk OAM modes, the main transmission OAM modes can be kept and distinguished by introducing some specific digital signal processing methods. Finally, for a verification of the presented VSASR method, several reflective metasurface antennas working at 10 GHz are designed, fabricated, and measured to generate different OAM vortex waves. Both the electromagnetic simulation and the measurement experiments are consistent well with the proposed theory analysis, which demonstrates the correctness and effectiveness of the proposed method.