  Wireless communications in the THz frequency band is an envisioned
revolutionary technology for sixth Generation (6G) networks. However, such
frequencies impose certain coverage and device design challenges that need to
be efficiently overcome. To this end, the development of cost- and
energy-efficient approaches for scaling these networks to realistic scenarios
constitute a necessity. Among the recent research trends contributing to these
objectives belongs the technology of Reconfigurable Intelligent Surfaces
(RISs). In fact, several high-level descriptions of THz systems based on RISs
have been populating the literature. Nevertheless, hardware implementations of
those systems are still very scarce, and not at the scale intended for most
envisioned THz scenarios. In this paper, we overview some of the most
significant hardware design and signal processing challenges with THz RISs, and
present a preliminary analysis of their impact on the overall link budget and
system performance, conducted in the framework of the ongoing TERRAMETA
project.
