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.