Terahertz wireless communication systems: challenges and solutions for realizations of effective bidirectional links

Wireless communication systems have evolved through a pursuit for broader bandwidths and a drive to higher frequencies. The drive has continued to present day and is now approaching the terahertz (THz) spectrum, where there exists great potential for broadband communication—and equally great challenges. Of note are the challenges of mobility for conventional THz transmitters, which have low transmitted powers, large sizes, and high power consumption. The proposed work recognizes these challenges and introduces the concept of retro-modulation in passive THz transceivers to have them establish passive THz links. Conventional (active) THz transceivers and links are contrasted to the proposed (passive) THz transceivers and links, with experimental and theoretical results given for THz retro-modulators having corner-cube and spherical retroreflectors with optical and electrical modulators. Ultimately, the findings show that passive THz links with high-frequency electronic transmitters and detectors and the proposed THz retro-modulators are capable of operation with signal-to-noise ratios between 10 to 20 dB at 300 GHz. Such findings open the door to future bidirectional THz wireless communication systems with mobile THz transceivers.