Generating and Detecting Broad-Band Underwater Multiple OAMs Based on Water-Immersed Array

In this paper, we focus on the generation of broadband underwater vortex waves carrying multiple OAMs. Based on a wideband underwater antenna, a water-immersed horn antenna array is designed and tested. The experimental results, which are in agreement with the simulation ones, validate that the proposed antenna array can readily generate high-quality vortex waves. To further validate the performance of the proposed underwater antenna array, experimental verifications of 2-D underwater imaging for the targets of two corner reflectors have been carried out, and the result shows that the targets can be distinguished efficiently. Meanwhile, two generation methods and one detection method of the multiplexed OAMs are also presented, from which the multiplexed OAMs can be generated and detected efficiently. And the performances of two generation methods have also been compared and discussed, from which we can know that the first generation method with a smaller structure costs lower and is more efficient.