A novel method to increase the accuracy of material characterization using free space transmission measurements

This paper describes a method to accurately determine the electromagnetic material properties of thin dielectric sheets. For non-magnetic materials, free space transmission measurements relative to an empty setup are sufficient to determine the complex permittivity of the sheet material. Measurements have been performed on a thin resistive sheet and a transformation procedure has been applied where the edge distortion at the lower frequency band is reduced. This is accomplished by shifting the band limited frequency spectrum down to DC before applying an inverse Fourier for gating purpose. The procedure yields accurate material characterization over the entire measured frequency band