A Resonance-Based Approach to Effective Dielectric Permittivity Evaluation of Transmission Lines up to 500 GHz

Precise characterization of transmission line (TL) properties at sub-terahertz frequencies is essential for reliable high-frequency circuit design. This study experimentally validates the probe backside reflection (PBR) method for evaluating the effective dielectric permittivity ($\varepsilon _{\text {eff}}$) and$Q$-factor of TLs, including a new analysis technique for improving the evaluation accuracy of$\varepsilon _{\text {eff}}$. Unlike the conventional thru-reflect-line (TRL) method, which requires long TL and large chip areas, the PBR method enables accurate measurement with a shorter line. The PBR method with the proposed analysis technique enables providing reasonable$\varepsilon _{\text {eff}}$and$Q$of TL in the successive frequency bands up to 500 GHz.