Transmission-Distance Limits of Gap Waveguide Technologies for 6G Applications

This study evaluates the feasibility of gap waveguides (GWs) for 6G applications within the International Telecommunication Union's recommended 275–325-GHz band, addressing the critical need for high-capacity, energy-efficient waveguiding solutions at sub-mmWave frequencies. We design ridge, groove, mushroom, and microstrip GW technologies for single-mode propagation at a center frequency of 300 GHz, investigating their transmission-distance limits through capacity and energy efficiency analyses that account for dispersion and attenuation. Our findings uniquely demonstrate that mushroom and microstrip GWs meet 6G requirements—achieving a peak data rate of 1 Tbps and energy efficiency below 1 pJ/b—up to a maximum length of 10 mm, outperforming traditional waveguide technologies in this frequency range. This work not only provides a foundational framework for GW design in 6G systems but also highlights their practical relevance for enabling ultra-high-speed, low-power communications, paving the way for future advancements in sub-mmWave technology.