A Review on Antenna Technology Developments for Sub-THz Wireless Communication: Application, Challenges and Opportunities

This paper analyzes state-of-the-art antenna concepts in the higher millimeter-wave frequency range (90-300 GHz), commonly referred to as the sub-THz frequency range. As the sub-THz range is still an emerging field of research, the aim of this review is to present and discuss different approaches and concepts reported in literature in the areas of antenna-in-package (AiP), antenna-on-chip (AoC) and other sub-THz antenna technology, focusing on the gain and occupied area parameters. Based on the analysis, it is concluded that AiP and AoC systems are very promising for highly integrated solutions requiring a small form factor, such as inter-device communication. At the same time, other concepts such as lens antennas provide a better solution for high-gain applications like fronthaul/backhaul scenarios. For D-band, a patch-AiP is the dominant antenna choice, but for H-band tailoring the antenna type to a specific application is highly recommended. The challenges involved in designing, manufacturing and measuring sub-THz antennas are best represented by the fact that only 26% of the listed AiP and AoC antennas operating above 200 GHz have documented performance measurements. This can be addressed by choosing the right manufacturing technology as well as measurement setup and corresponding calibration.