A new free-wave dielectric and magnetic properties measurement system at millimetre wavelengths

A new free-wave method for measuring complex permittivity and permeability of materials at mm-wave frequencies is introduced. The use of time gating for removing the unwanted reflections within the sample, and its advantages in simplifying the calculations and decreasing the dependence of measurement accuracy on frequency are discussed. The error due to imperfect gate parameters is derived by simulation, and the optimum sample thickness is recommended. Examples of results obtained from measurements of ferrite and dielectric samples are presented and discussed.<>