Generation of radio beams carrying OAM basing on coaxial waveguide

This paper presents a kind of circular loop antenna (CLA) constructed by coaxial waveguide, which is able to generate radio beams carrying orbital angular momentum (OAM) under the condition of dual port excited. The proposed CLA can reconfigure OAM modes with opposite sign by retrieving the alternative ports. Method induced in this work to design CLA based OAM generator could be extended to other types of transmission line structure, which makes the discussions presented in our porotypes be significant for the research and application of the OAM beams in low frequency.