Eight-mode OAM microstrip antenna based on multi-ring structure

This paper presents a multi-mode orbital angular momentum(OAM) wave element antenna design. These eight-mode OAM beams are generated simultaneously using four concentric shorted annular ring microstrip patches, and the antenna is simple in structure and small in size. Simulation and test results show that eight modes (l=±1, ±2, ±3, ±4) have good vortex phase characteristics. Meanwhile, the element gains of corresponding modes are 4.8 dBi, 4.1 dBi, 5.1 dBi, and 5.3 dBi, respectively, and the impedance bandwidth of all modes are greater than 100 MHz. It can provide a new possibility for future multi-mode OAM wave applications.