Generation of dual‐mode PS‐OAM beams using a Vivaldi antenna array

Abstract The paper proposes a single antenna that can generate dual‐mode plane spiral orbital angular momentum (PS‐OAM) beams. Six Vivaldi antennas placed in a tangential circular array make up the antenna, and the antenna is etched onto a substrate material and has a flat design, allowing for easy integration with other system components. The neighbouring ports of the antenna elements have phase differences, so phase‐shifting in the feeding network is unnecessary. When fed with the same phase and amplitude, the antenna can produce PS‐OAM beams with mode +1 at 7 GHz and mode +2 at 14 GHz, and the measured purity is 80.6% and 63%, respectively. The method may provide a new way to produce multi‐mode orbital angular momentum.