Analysis and characterization of passive filters based on metasurfaces for Terahertz wireless communications

Nowadays, the “Big Data” concept is well known and it has brought many consequences such as increased data traffic. However, the main actors that have contributed to the increase in wireless data traffic are the exponential growth of connected devices and the densification of antennas. Thus, the scientific community has focused its work on developing devices that can work in higher bands than the present, encouraging the development of technology for 5G and eventually 6G. Nevertheless, the present wireless communications systems do not yet exceed 100 GHz. Among the candidates, the Terahertz (THz) frequency range (0.1–10 THz) is a possible solution to the aforementioned requirement. For this reason, both Industry and Academia have focused their interests on the ability to govern THz radiation to exploit it in various scientific and technological fields such as: astronomical instrumentation, imaging for medical diagnosis, spectroscopy for qualitative and quantitative analysis of chemical substances and compounds, and wireless communications. The quasi-absence of high-performance devices such as sources and detectors has originated the so-called “THz gap”. However, the research community is investing resources in the analysis, characterization, and production of devices operating in the THz range. These devices can be distinguished mainly into two categories: active and passive. The former produce, feed, and convert the electromagnetic wave propagation in the THz range, whereas the latter are suitable for absorption, reduction, focusing, and filtering operations (the latter are found in both categories).