Unique-Solution Single-Sample Complex Dielectric Characterization Through Linear Phase Approximation

Abstract

This paper presents a transmission-only (TO) approach that solves the long-standing problem of transmission phase ambiguity. The approach considers a linear frequency-dependent phase approximation to derive the phase mode value analytically and uniquely based on three parameters: the first phase jump frequency, the start frequency, and the start phase value. This formulation leads to a unique propagation constant, easy-to-compute for low-band and wideband applications. In addition, the approach presents a non-iterative loss extraction method based on analytical formulation and curve-fitting. Beyond, the approach corrects standing waves’ effect, making it suitable for matched and mismatched lines without any initial guess of the material properties. Numerical and experimental validations confirm the proposed approach for weakly and highly dispersive microstrip samples, including low- and high-loss dielectrics.

Keywords

• Dielectric constant
• dielectric losses
• transmission line measurements