Generation of an Orbital-Angular-Momentum-Mode-Reconfigurable Beam by a Broadband 1-Bit Electronically Reconfigurable Transmitarray
Baiyang Liu, Sirong Li, Yejun He, Yin Li, Sai‐Wai Wong
Abstract
Broadband orbital-angular-momentum (OAM) multiplexing is of great interest due to its ability to increase channel capacity in wireless communications. However, broadband OAM-mode-reconfigurable transmitarrays have yet to be developed. Here, a broadband 1-bit electronically reconfigurable transmitarray for OAM-mode-reconfigurable beam generation is proposed, fabricated, and tested. The OAM transmitarray includes $20\ifmmode\times\else\texttimes\fi{}20$ elements with a 1-bit phase resolution, each element is controlled by two $p$-$i$-$n$ diodes with a minimum insertion loss of 0.9 dB and a 3-dB transmission bandwidth of 17.1%. A nearly perfect 1-bit phase resolution is obtained by reversing the current. The OAM mode can be switched between $l=+1$ and $l=+2$ based on a steering-logic board. Both simulation and experiment results show the transmitarray can generate a broadband OAM-mode-reconfigurable beam from 9.5 to 10.5 GHz. The proposed transmitarray may have potential applications in broadband OAM-multiplexing communications.