Improved Method for Permittivity Determination of Dielectric Samples by Free-Space Measurements

A new deembedding technique is proposed for relative complex permittivity \varepsilon _{r} determination of dielectric materials using gated free-space measurements. Its three main features are 1) it does not require any formal calibration procedure (calibration-free); 2) it is position-insensitive; and 3) it extracts ripple-free \varepsilon _{r} due to gating process. The objective function derived to determine \varepsilon _{r} by the proposed method is validated by free-space measurements of three dielectric samples (polypropylene, polyethylene, and polyoxymethylene). Besides, the accuracy of our method is compared with the accuracy of other calibration-free and calibration-dependent methods in the literature.