Utilizing OAM in Terahertz Frequency Band to Improve Transmission Capacity

As one of the potential 6G technologies, terahertz positively affects the data rate, supports ultra-dense connection, and realizes low-latency transmission. How to make better use of the terahertz frequency is one focus of the future 6G research. Moreover, orbital angular momentum (OAM) is promised to effectively increase the system capacity with reduced hardware complexity. The application of OAM in the terahertz frequency band is investigated in this paper, giving the pros and cons. First, the characteristics of the terahertz channel are analyzed, and the feasibility of applying terahertz OAM is confirmed. Then, the investigation of terahertz OAM proves that working at terahertz frequency can effectively solve the beam divergence, and a novel receiving antenna design is proposed to reduce the receiving aperture size further. Finally, the capacity characteristics of OAM and MIMO in the terahertz frequency band are analyzed to prove the effectiveness and the necessity of applying terahertz OAM.