Compact Slow-Wave Transmission Line Design with High Effective Dielectric Constant

This paper presents the design and simulation of transmission lines with high propagation constants using slow-wave architecture integrated with coplanar waveguides (CPWs) in 65nm BULK CMOS technology. The slow-wave structure enables the design of more compact and efficient transmission lines by reducing the signal's propagation speed. Electromagnetic simulations were conducted using HFSS software within the 0 to 250 GHz frequency range, with a detailed analysis of performance metrics such as propagation constant, attenuation, effective dielectric constant feff), and quality factor. The results indicate that slow-wave transmission line (SWTL) achieves the same transmission as designed CPW structure while occupying 30% less area, significantly minimizing losses in compact form. Furthermore, the SWTL provides high quality factor up to high frequencies of 250 GHz, offering distinct advantage in millimeter-wave and particularly sub-terahertz applications with more efficient transmission compared to conventional structures. This design stands out as low-loss, space-efficient solution for high-frequency RF systems.