A Noniterative and Efficient Technique to Extract Complex Permittivity of Low-Loss Dielectric Materials at Terahertz Frequencies

Abstract

In this letter, a noniterative technique is proposed to efficiently extract complex permittivity $(\varepsilon)$ of low-loss dielectric materials at terahertz frequencies while mitigating the effects at Fabry–Perot frequencies. For this goal, the formula of $\varepsilon $ with little resonance is first derived by applying boundary conditions for the transmission-reflection-based free-space method. In order to demonstrate the advantages of the proposed technique, we compared the proposed technique with the classical Nicolson–Ross–Weir method and the Newton–Raphson method. The proposed noniterative technique is verified by experiments and simulation at 220–325 GHz.