Generation of Multi-Mode OAM Waves Through Programmable 1-bit Digital Coding Metasurfaces

In order to exploit orbital angular momentum (OAM) transmitting data, multiple-mode OAM waves should be generated preferably by a fixed antenna. In this paper, a programmable 1-bit digital coding metasurface is presented for the generation of multi-mode converged OAM waves. The proposed reconfigurable element consists of a microstrip patch, a PIN diode, and a DC biasing circuit. Through electronically controlled the PIN diode ON and OFF, two states with a phase difference of 180 degrees, i.e., "0" and "1" states, can be realized. By properly designing varying states of each element on the metasurface array, the OAM waves can be generated and dynamically reconfigured among l = 0 and l = 1 modes at 7.77GHz. As a consequence, it is potential in wireless communication applications.