A Generalized Formulation for Permittivity Extraction of Low-to-High-Loss Materials From Transmission Measurement

We have derived a one-variable metric function for fast computations of the relative complex permittivity of low-to-high-loss materials from S ₂₁ measurement at one frequency. We present how this function can be applied for different applications (e.g., relative complex permittivity measurement of a thin low-loss material). In addition, it can be applied as a measurement tool in broadband applications for samples with substantiate lengths, which demonstrate low-loss property at lower frequency bands and high-loss property at higher frequency bands. The derived expressions can work very well in limited frequency-band applications or for dispersive materials since it is based on point-by-point (or frequency-by-frequency) extraction. We measured the relative complex permittivity of two test samples (a low- and high-loss sample) for validation of the derived expressions.