Improved Method for Permittivity Determination of Dielectric Samples by Free-Space Measurements
Uğur Cem Hasar, Yunus Kaya, Hamdullah Öztürk, Mucahit Izginli, Mehmet Ertuğrul, Joaquim J. Barroso, Omar M. Ramahi
Abstract
A new deembedding technique is proposed for relative complex permittivity <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon _{r}$ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon _{r}$ </tex-math></inline-formula> due to gating process. The objective function derived to determine <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon _{r}$ </tex-math></inline-formula> 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.