Vortex wave generation using single‐fed circular patch antenna with arc segment

Combined with characteristic mode analysis, the idea of degenerate mode synthesis can be used to guide the construction of a single antenna, which radiates vortex electromagnetic waves carrying orbital angular momentum (OAM). In this paper, an arc segment outside a circular patch is applied to disturb the structure symmetry to achieve a single‐fed antenna with orthogonal degenerate mode synthesis. Experimental results show that degenerated characteristic modes of circular patches radiate vortex waves one order lower than source modes. If two degenerate TM21 source modes are superimposed, the first‐order OAM mode is generated. Since the arc segment as a disturbance element is independent of the radiation element, OAM modes of different orders can be realized by adjusting its length.