Generation of Off-Axis Different-Order Bessel Beams Using a Transmissive Metasurface

This article proposes a novel approach for generating off-axis different-order Bessel vortex beams using a transmissive metasurface. The method enables precise control over zero-order and high-order Bessel beams while maintaining good vortex characteristics. The metasurface unit provides a high transmission coefficient of over −1 dB and a phase shift exceeding 360°. Simulations were conducted for three modes and different angles of Bessel beams at a central frequency of 10 GHz. The analysis of amplitude, phase distribution, and orbital angular momentum (OAM) mode purity demonstrated that off-axis Bessel beams of different orders generated through geometrical optical transformation exhibit superior performance at large deflection angles, satisfying vortex wave characteristics with a purity exceeding 0.8. This flexible method for controlling deflected zero-order and high-order Bessel beams while ensuring excellent beam performance makes it suitable for wireless power transfer and communication applications.