Realization of Third-Order OAM Mode Using Ring Patch Antenna
Weiwen Li, Jianbin Zhu, Yongcong Liu, Baoping Zhang, Yanhui Liu, Qing Liu
Abstract
Using single structure antennas to generate electromagnetic waves with orbital angular momentum (OAM) modes can greatly simplify the OAM application systems. However, at present, there is a lack of theoretical guidance for the realization of OAM modes using only a single antenna. In this communication, the characteristic mode theory (CMT) is applied to analyze the current wavemodes of the patch antenna. Then, the orthogonal degenerate modes are selected and the feeding structure is determined to obtain the desired OAM mode. For example, a third-order OAM radio wave is implemented by a ring patch antenna, and the performance of this OAM mode is explained by using the modal excitation coefficient. It is verified that the CMT is an effective analysis tool for a single antenna to achieve OAM modes.