Solid-State Terahertz Circuits for 6G: A Review

Terahertz communication is anticipated to play a pivotal role in applications like super-capacity data retrieval, ultra-high-speed short-distance transmission, holographic communication, and micro-sized communication. Emerging scenarios such as the sixth generation (6G), integrated sensing and communication, the metaverse, and autonomous agent networking are also poised to benefit. Additionally, it promises high-precision positioning and high-resolution perceptual imaging for networks and terminal devices. This paper provides a comprehensive overview of the current performance, developmental trends, and measurement techniques associated with solid-state terahertz circuits and communication systems. Regarding circuits, the research and development of single-function circuits in the terahertz band have reached maturity. Traditional single-function circuits continue to evolve towards higher frequency bands (exceeding 1 THz), with reduced loss and improved efficiency. Concurrently, building upon these traditional circuits, researchers have introduced innovative integrated circuit designs and layout techniques to minimize system volume. Solid-state terahertz communication systems are also progressing towards elevated carrier frequencies, faster communication rates, phased arrays, and full-duplex communication. Through collaborative efforts, the global academic and industrial communities are intensifying their focus on terahertz key technologies and prototype system validation, aiming to bolster industrial growth and ecosystem development.