Measurement of microwave permittivity using a six-port reflectometer with an open-ended coaxial line

A nondestructive broadband permittivity-measurement method using an automatic six-port reflectometer is presented. The impedance sensor is an open-ended coaxial line terminated by a semi-infinite medium. The equivalent model of the sensor used is based on an equivalent effective transmission-line length which models the fringing field at the extremity of the probe. The proposed method is useful to measure relatively high-loss dielectric liquids and provides a precision comparable to other methods already in use; however, the equipment costs are considerably reduced