Alsharif, M. H. & Nordin, R. Evolution towards fifth generation (5G) wireless networks: current trends and challenges in the deployment of millimetre wave, massive MIMO, and small cells. Telecommun. Syst. 64, 617â637 (2017).
Dang, S., Amin, O., Shihada, B. & Alouini, M.-S. What should 6G be? Nat. Electron. 3, 20â29 (2020).
Akyildiz, I. F., Kak, A. & Nie, S. 6G and beyond: the future of wireless communications systems. IEEE Access 8, 133995â134030 (2020).
Rappaport, T. S. et al. Wireless communications and applications above 100 GHz: opportunities and challenges for 6G and beyond. IEEE Access 7, 78729â78757 (2019).
Nagatsuma, T., Ducournau, G. & Renaud, C. C. Advances in terahertz communications accelerated by photonics. Nat. Photon. 10, 371â379 (2016).
Akyildiz, I. F., Jornet, J. M. & Han, C. Terahertz band: next frontier for wireless communications. Phys. Commun. 12, 16â32 (2014).
Koenig, S. et al. Wireless sub-THz communication system with high data rate. Nat. Photon. 7, 977â981 (2013).
Fu, X., Yang, F., Liu, C., Wu, X. & Cui, T. J. Terahertz beam steering technologies: from phased arrays to field-programmable metasurfaces. Adv. Opt. Mater. 8, 1900628 (2020).
Monnai, Y., Lu, X. & Sengupta, K. Terahertz beam steering: from fundamentals to applications. J. Infrared Millim. Terahertz Waves 44, 169â211 (2023).
Tan, Y. J. et al. Self-adaptive deep reinforcement learning for THz beamforming with silicon metasurfaces in 6G communications. Opt. Express 30, 27763â27779 (2022).
Sengupta, K. & Hajimiri, A. A 0.28 THz power-generation and beam-steering array in CMOS based on distributed active radiators. IEEE J. Solid-State Circuits 47, 3013â3031 (2012).
Tousi, Y. & Afshari, E. A high-power and scalable 2-D phased array for terahertz CMOS integrated systems. IEEE J. Solid-State Circuits 50, 597â609 (2015).
Che, M. et al. Optoelectronic THz-wave beam steering by arrayed photomixers with integrated antennas. IEEE Photon. Technol. Lett. 32, 979â982 (2020).
Sengupta, K., Nagatsuma, T. & Mittleman, D. M. Terahertz integrated electronic and hybrid electronicâphotonic systems. Nat. Electron. 1, 622â635 (2018).
Zeng, Y. et al. Electrically pumped topological laser with valley edge modes. Nature 578, 246â250 (2020).
Shalaev, M. I., Walasik, W., Tsukernik, A., Xu, Y. & Litchinitser, N. M. Robust topologically protected transport in photonic crystals at telecommunication wavelengths. Nat. Nanotechnol. 14, 31â34 (2019).
Gao, F. et al. Topologically protected refraction of robust kink states in valley photonic crystals. Nat. Phys. 14, 140â144 (2018).
Dong, J.-W., Chen, X.-D., Zhu, H., Wang, Y. & Zhang, X. Valley photonic crystals for control of spin and topology. Nat. Mater. 16, 298â302 (2017).
Ma, T. & Shvets, G. All-Si valley-Hall photonic topological insulator. New J. Phys. 18, 025012 (2016).
Yang, Y. et al. Terahertz topological photonics for on-chip communication. Nat. Photon. 14, 446â451 (2020).
Kumar, A. et al. Phototunable chip-scale topological photonics: 160âGbps waveguide and demultiplexer for THz 6G communication. Nat. Commun. 13, 5404 (2022).
Jia, R. et al. Valley-conserved topological integrated antenna for 100-Gbps THz 6G wireless. Sci. Adv. 9, eadi8500 (2023).
Hatsugai, Y. Edge states in the integer quantum Hall effect and the Riemann surface of the Bloch function. Phys. Rev. B 48, 11851â11862 (1993).
Balanis, C. A. Modern Antenna Handbook (Wiley, 2011).
Sen, P., Siles, J. V., Thawdar, N. & Jornet, J. M. Multi-kilometre and multi-gigabit-per-second sub-terahertz communications for wireless backhaul applications. Nat. Electron. 6, 164â175 (2023).