Reflected Group Delay for Dielectric Characterization of Microstrip Substrates Using Coaxial Resonator

This paper introduces a novel method for dielectric characterization using the reflected group delay of a capacitively coupled coaxial resonator attached to a microstrip line on a substrate under test. The method operates in an over-coupled state, allowing it to characterize materials over a wider frequency range compared to techniques that use critically coupled resonators. Simulation results demonstrate the effectiveness of the method in characterizing materials with dielectric constants ranging from 2.2 to 9.2, with an error of less than 2 %. Additionally, the method is also effective in measuring loss tangent with an error of less than 100 %. The proposed approach is simple, efficient, and easy to implement, making it suitable for dielectric characterization in both research and industrial settings.