Wideband One-Port Complex Permittivity Measurement of Flexible Shielding Materials Using a Radial Waveguide

A new wideband technique for determining the complex permittivity of flexible materials between 1 to 6 GHz is presented. In contrast to other methods - which mostly assume a planar geometry and require large samples and transmission lines for wideband measurements, this technique employs a compact setup. By taking advantage of the flexibility of the sample, we introduce a cylindrical measurement configuration capable of determining the complex permittivity of the material under test. Numerical simulations were performed on lossless and dispersive materials to demonstrate the method's applicability. To further validate the proposed method, a radial waveguide along with its own calibration set was constructed using 3D printing and used to measure a sample of Polylactic Acid (PLA).