Plasmonic solenoid: Future progress in wireless communications will rely on breakthroughs in generation, detection, and conversion of terahertz radiation. The transition to 6G , the 300 GHz band for wireless will be transformational. It will completely change the way we work, learn, communicate, do business, commute and get medical treatment. These breakthroughs will come from using 3D plasmonic, of which the plasmonic solenoid is an example.