Integrated circuits for terahertz communication beyond 100 GHz: Are we there yet?

The evolution of the 5G paradigm exploiting millimeter-wave frequencies have raised interest in the spectral bands above 100 GHz ranging up to 1000 GHz for wireless communication and sensing. In the last decade, there has been a significant upsurge of research in the field of integrated THz technology that has focused on enabling efficient and compact Terahertz systems operable at room temperature and deployable at large scales. In this, silicon-based integrated circuit technology can potentially provide a scalable platform. The benefits span from its level of integration right from the THz front-end to the back-end digital signal processing to high yield and low cost exploiting economies of scale. The impact of such silicon-based systems in the sister millimeter-wave bands (28/38/60/77 GHz) have already been seen in automotive radars and are starting to surface for 5G applications and beyond. The question is if this success can be translated to technologies beyond 100 GHz and extending up to 1 THz for short-range to long-range communication links. Silicon is not the only contender in the space. In the landscape of integrated technologies ranging from ICs (CMOS, SiGe to III-V) to photonics and other technologies, it is not clear how the pie be divided. This paper will focus on some of the latest advances in silicon-based THz systems and future challenges that span across all levels of abstraction in this uncharted frequency spectrum.