MICROWAVE METHOD FOR THICKNESS-INDEPENDENT PERMITTIVITY EXTRACTION OF LOW-LOSS DIELECTRIC MATERIALS FROM TRANSMISSION MEASUREMENTS

A non-resonant microwave method has been proposed for complex permittivity determination of low-loss materials with no prior information of sample thickness. The method uses two measurement data of maximum/minimum value of the magnitude of transmission properties of the sample to determine an initial guess for permittivity and find the sample thickness. An explicit expression for sample thickness and two expressions for inversion of the complex permittivity of the sample are derived. The method has been validated by transmission measurements at X-band (8.2-12.4 GHz) of a low-loss sample located into a waveguide sample holder.