Orbital Angular Momentum Modes Filtering for Multiple Modes Vortex Wave Multiplexing

In this paper, an orbital angular momentum (OAM) modes filtering method for multiple modes multiplexing is proposed. The whole aperture sample reception (WASR) method is used first for multiple OAM modes reception based on the fast Fourier transform (FFT). Then the chirp z-transform (CZT) algorithm is used for multiple OAM modes filtering. For demonstrating the effectiveness of the method, a classic uniform circular array antenna is designed to generate multiple combination OAM mode simultaneously. And different filtering results are shown through applying the CZT algorithm.