Measurement of sheet-material electrical properties: Extending lumped-element methods to 10 GHz

A procedure for measuring the complex dielectric permittivity ε̂ of sheet materials, which uses a lumped-element approach for calculating ε̂ is described. Air is used as a standard material to determine the stray capacitance, inductance, and resistance of the sample holder. With a careful determination of these stray parameters, the frequency limit for these measurements can be extended up to 10 GHz. The residual scatter in the data, after the data have been corrected for stray capacitance, resistance, and inductance effects, is typically below 1% for ε′ and is of the order of 0.001 for tan δ. The procedure uses a low-cost sample holder and a conventional network analyser.