The Evolution of Wireless Communication with the THz Spectrum: New Horizons in 6G

Terahertz (THz) communication, which operates in the frequency range from 0.1 THz to 10 THz, has emerged as a key technology for next-generation wireless networks, especially in the 6G era. With its ultra-wide bandwidth and high data rate capabilities, THz communication enables applications such as high-speed wireless transmission, integrated sensing and communication (ISAC), and real-time intelligent networking. However, the practical deployment of THz systems faces significant challenges, such as high path loss, atmospheric attenuation, and hardware limitations. This paper provides a comprehensive overview of THz communications, discussing its fundamental principles, its role in 6G networks, and key enabling technologies such as multiple-input multiple-output (MIMO), beamforming, reconfigurable intelligent surfaces (RIS), and multicarrier modulation techniques. We also explore the limitations of THz technology and how artificial intelligence (AI)-driven solutions can address these challenges and improve system efficiency and security. Finally, we present future research directions that need to be explored in order to fully realize the potential of THz communications in 6G networks.