Permittivity characterization from open-end microstrip line measurements

A broad-band method for measuring the complex permittivity of isotropic film-shaped materials at low microwave frequencies is presented. The characterized material is the substrate of an open-end microstrip line used as sample-cell. Complex permittivity is computed from S11 reflection parameter measurement of open-end microstrip cell using analytical relationships, which decrease the computation time. Vector network analyzer and high-quality on-microstrip test fixture are used for the measurement bench. Measurements over 0.01 GHz-3 GHz frequency range with several nonmagnetic materials show good agreements between measured and predicted results. © 2007 Wiley Periodicals, Inc.