Evaluation of Dielectric Measurements upon Thin Single Layer Solids using OpenCoaxial Probe Technology

Measurements of the complex permittivity of materials as functions of frequency provide valuable information in different fields of engineering, industry, medicine and physical chemistry. Open-Ended Coaxial probes (OCP) are commonly used as nondestructive testing tools for dielectric analysis. The method, although nondestructive, does have limitations. For example, if there is an air gap between sample and probe, the discontinuity in the normal electric field causes a considerable error in the predicted permittivity. Even a small gap of the order 10μm in thickness can produce large errors in permittivity measurement by sensors (10% or more) because it lies in the region where the fringing fields are most intense [1]. For this reason, usually the probe use has been limited to liquid and semiliquid measurements, where good contact can be obtained.