Generating the dual-band and multimode OAM by irregular pentagonal patch antenna array

This Letter presents an irregular pentagonal patch array antenna with a multilayer structure for dual-band and multimode orbital angular momentum (OAM) generation. An irregular pentagonal patch antenna with U-shaped slots resonating at different frequencies is designed as the array's element. The proposed antenna array consists of two uniform circular microstrip antenna arrays and two phase-shifting feeding networks. It can be used to generate OAM mode l = − 1, 1 at 3 GHz and OAM mode l = −2, 2 at 6 GHz. The simulated near-field phase distributions images of different OAM modes are obtained, which have verified the OAM generation. This proposed array antenna has the possibility to generate a total of six different OAMs in three frequency bands, by changing the number of array elements and optimising the irregular pentagonal patch antenna. This design may provide a new idea for the generation multimode vortex electromagnetic wave.