A low sidelobe design method for planar array vortex beams

This paper proposes a method for designing low sidelobe vortex beams based on planar annular arrays. The effects of the inner and outer radii of the planar annular array on the sidelobe level, divergence angle, and beamwidth of the vortex beams is discussed. Simulation and experimental results show that for a single-mode vortex beam antenna, the simulated sidelobe levels of the 1st, 2nd, and 3rd-order modes are below −32.3 dB, −32.8 dB, and −30.0 dB, respectively, for a multi-model vortex beam antenna, the simulated and measured sidelobe levels of the 1st, 2nd, and 3rd-order modes are lower than −29.1 dB, −30.3 dB, and −25.3 dB, and −25.4 dB, −30.0 dB and −24.6 dB, respectively. The method, based on an optimized annular array structure and non-uniform Chebyshev excitation, can effectively suppress the sidelobe level of vortex beams and is applicable to the antenna design of multi-modal vortex electromagnetic wave communication systems.