Measurement methods for the permittivity of thin sheet dielectric materials

This paper presents a new method for the determination of the complex permittivity of thin sheet dielectric materials that are flexible and elastic. Instead of the traditional method to install a doughnut shape sample in the transverse plane used in transmission line methods, most widely used methods for broadband permittivity measurements, a thin sheet sample is installed onto the outer conductor of the coaxial transmission line. The proposed method has much large sensitivity compared to the traditional one and is a broadband technique useful for thin sheet materials. Measurement results and comparison with other approaches agree very well, particularly at high frequency range.