An Electronically Mode Reconfigurable Orbital Angular Momentum Array Antenna.

In this paper, an array antenna for generating multi-mode orbital angular momentum (OAM) vortex waves and having electrically controlled mode reconfigurable function is proposed. The proposed antenna is based on a reconfigurable feed network (RFN) consisting of multiple PIN diodes as reconfigurable switches, a direct current (dc) control board and a 2 x 4 radial uniform circular array. By controlling the coding sequence of the corresponding PIN diode dc bias voltage on the RFN using a programmable microcontroller, the OAM modes generated by the proposed antenna can be dynamically reconfigured between 1 = 0, +/- 1, and +/- 2. Moreover, the OAM beams can be generated in a wide frequency band of 5.5-6.1 GHz and 5.65-6.1GHz for 1 = +/- 1, +/- 2 modes and 1 = 0 mode, respectively. The prototype of the proposed antenna is simulated and fabricated to validate the proposed design. Both far-field and near-field experiments were performed to verify the feasibility of the proposed design. The results of the numerical simulation and measurement have good agreement with each other.