Up until recently, the terahertz frequency range (0.3 to 3THz) has been mostly addressed by high-mobility custom III-V processes, bulky and expensive nonlinear optics, or cryogenically cooled quantum cascade lasers. A low-cost room temperature alternative will enable a wide range of applications in security, defense, ultra-high-speed wireless communication, sensors, and biomedical imaging not currently accessible due to cost and size limitations. CMOS can potentially provide such a low-cost platform, but it requires novel techniques and architectures to generate, manipulate, radiate, and detect signals above transistor fmax, which are in the sub-THz frequency region in most of today’s nodes.