Generation and analysis of convergent vortex wave based on orthogonal waveform

Electrogenic vortex wave refer to the wave that carry orbital angular momentum (OAM) in the radio frequency (RF) domain. The OAM mode is expected to be initially explored and applied as a full novel spatial dimension resource. However, the radiation energy distribution pattern of electromagnetic vortex wave exhibits a central hollow. The energy hollow phenomenon has become one of the major drawbacks limiting the popularization of electromagnetic vortex wave. In this article, a generation scheme of convergent vortex wave is proposed and research generated by uniform circular array (UCA). Orthogonal waveforms are introduced into the antenna to change the phase relationship between the original signals so that the energy remains in the wave center region. The numerical results validate the effectiveness of the proposed scheme. The circular intensity disappears, while the spiral phase wavefront features can still be maintained.