Dielectric Constant Measurement Using Time-Domain Shifted Metal-Backing Measurements

A free-space microwave method is proposed for accurate dielectric constant
$\varepsilon _{r}$
measurement of flat dielectric samples using time-domain measurements. It does not require any reference data (calibration-independent) and thickness information for
$\varepsilon _{r}$
measurement. Besides, it uses only two power peaks of reflected signals of one sample with offset metal termination. It is first validated by simulations and numerical analysis. Free-space
$\varepsilon _{r}$
measurements of three low-loss dielectric samples [polypropylene (PP), polyethylene (PE), and polyoxymethylene (POM)] are then performed for validation of our method. Its accuracy is compared with the accuracies of similar methods in the literature.