Mode reconfigurable OAM helical array antenna for higher mode generation

Abstract

In this paper, an orbital angular momentum (OAM) mode reconfigurable antenna based on a uniform circular array (UCA) is presented. The phase superposition method is presented to overcome the limitation of the number of array units on the mode order in the conventional four‐element UCA antenna, which is limited to generating first‐order OAM beams. The unit phase is introduced by a bifilar helical antenna in this method, and the unit phase is superimposed with the feed phase of the UCA to enable the generation of 3rd‐order OAM beams from the four‐element UCA. At the same time, the DC signal‐controlled feed network assigns three distinct feed phases to the UCA, which realizes the reconfigurability of the three OAM beams. To achieve mode reconfigurability, 20 p‐i‐n diodes were integrated as switches in the feed network for controlling the ON/OFF status of p‐i‐n diodes in the feed network using DC signals. Finally, simulated and measured results show that three OAM beams (lz = −1, −2, and −3) have been generated in the frequency band from 10.6 to 11.8 GHz.