Quasi-Nondiffractive Multibeam Antennas Based on Phase Shift Surfaces

In this article, a method of generating quasi-nondiffractive multibeam is proposed. The phase synthesis method of the far-field multibeam antenna is introduced into the near-field to generate a quasi-nondiffractive multibeam. The optimization based on the reference phase of each beam superposition can effectively suppress the sidelobe of each beam and improve the efficiency of directional power transmission. Even if the Bessel beams are close enough to cause an overlap of their outer rings, it does not affect their nondiffractive characteristics. Four quasi-nondiffractive multibeam antennas are designed, and the results of electromagnetic numerical simulation, full-wave simulation, and experiments are in good agreement. The scan angle, depth of field, and ratio of the electric field magnitudes of each beam can be controlled independently. The proposed antennas make it possible to apply quasi-nondiffractive beams in fields of multitarget wireless power transmission and multiregion signal coverage.