An automated and nondestructive slot line measurement technique for complex permittivity materials

An automated and nondestructive slot line measurement technique for complex permittivity of phantom materials is presented. A flanged open-ended rectangular waveguide is used as the probe, which is placed in close contact with the materials under test. The reflection coefficient is measured by a CAT (computer aided test) system. The developed algorithm, which is built on a two-variable polynomial curve-fitting method, is applied to determine the complex permittivity. The test results show that the technique is not only cheap and easy to use, but also accurate in measuring a range of sample materials.