Microwave Vortex Transceiver System with Continuous Tunability Using Identical Plasmonic Resonators

Abstract Electromagnetic vortices have attracted vast interest for their unique physics and promising applications. Tremendous efforts have been devoted to vortex generations, but receiving vortex modes remains challenging and commonly requires spatial phase gradient measurements. Here, a compact microwave vortex transceiver system based on reversible superposition and decomposition of degenerate and orthogonal dipole modes is reported. Identical plasmonic resonators are designed as both transmitting and receiving antennas. The received vortex modes are conveniently characterized by amplitude and phase signals measured at the receiving resonator ports. The transmitted orbital angular momentum (OAM) can be continuously tunable while the topological charge maintains discrete values of ±1. A transceiver system for degradation and reconstruction of OAMs is experimentally constructed, which can dynamically tune the vortex modes via simple voltage modulations. This research provides a convenient solution to transmit and receive microwave vortices, and paves novel routes for sensing and wireless communications based on continuously tunable vortex modes.