Scattering Characteristics of Vortex Electromagnetic Waves for a Wedge

Vortex electromagnetic (EM) waves with orbital angular momentum (OAM) offer a new degree of freedom for radar detection. Although to date few researches on target scattering characteristics of vortex EM waves have been reported. In this paper, the backscattering characteristics of vortex EM waves for a perfectly conducting wedge is investigated experimentally using the radar cross section (RCS) calibration measurement method. The experimental results show that for vortex EM waves, due to the specific spatial distribution, the RCS fluctuation of vortex EM waves is different from that of plane EM waves, and it varies with the OAM mode of the incident wave. The RCS of OAM beams is higher than that of the plane wave in some incident direction. This phenomenon indicates that vortex EM waves are more effective than plane EM waves to detect the low RCS target in some direction. And vortex EM waves of different OAM modes may be helpful to detect the low RCS target by increasing the RCS of the target.