Effective Realization of Higher Order Circular Polarized OAM Mode Circular Patch Antenna

Characteristic mode theory offers valuable insights into the realization of orbital angular momentum (OAM) waves using a single patch antenna. However, realizing a circularly polarized higher-order OAM wave patch antenna remains challenging. This brief provides a theoretical framework for effectively realizing a circularly polarized higher-order OAM wave antenna. This brief presents a comparative analysis between a ring and a disk patch antenna, equipped with a proposed symmetric dual-feed configuration to efficiently excite circularly polarized
$4^{th}$
order OAM waves.The results show that a ring patch antenna outperforms the disk patch antenna in higher-order circularly polarized OAM wave quality, exhibiting superior characteristics in mode purity, field rotation, near-field behavior, and radiation pattern.