New Measurement Technique for Complex Permittivity in Millimeter-Wave Band Using Simple Rectangular Waveguide Adapters

Abstract

This research presents a novel methodology for measuring the complex permittivity of a material under test (MUT) in a millimeter-wave (mmWave) band by using two rectangular waveguide adapters. Contrary to the conventional Nicolson-Ross-Weir (NRW) method, the proposed complex permittivity measurement method does not require a material fabrication process for exact MUT insertion into a waveguide. In our complex permittivity measurement, simple commercial waveguide adapters are employed instead of large flange structures. The proposed complex permittivity measurement of a non-destructive MUT is achieved by combining the NRW method, the Gaussian weighting moving average filtering technique, a full-wave electromagnetic analysis, and an optimization technique. Furthermore, the proposed methodology is validated by fabricating a Teflon-based MUT and by measuring the complex permittivity of the MUT in the Ka band (26.5–40 GHz). The results indicate that the proposed methodology exhibits good agreement with the data sheet.

Electrical Properties of Ferrite Absorber in High-Band 5G System Determined by Open Coaxial Probe and Free Space Methods

“…where 𝛾 =𝑗2𝜋 𝜆 ⁄ represents the propagation constant of free space (wave constant), and 𝜆 is the wavelength in free space. Based on equations ( 20) and ( 21), we can determine S from the scattering matrix as [21,22] :…”

“…Based on equations (30) and (31), we can express the complex parameters 𝜀 * and i 𝜇 * as a dependence on the parameters of the scatter matrix S [18,20,21,22]:…”