A new method of obtaining the permittivity of liquids using in-waveguide technique

This letter presents a method of measuring the permittivity of a liquid contained inside a waveguide, having a four-boundary arrangement. Previous methods employ an expression for the total transmission through a four boundary cell. We present a new method in which the permittivity is obtained by de-embedding the S-parameters of the sample from the S-parameters measured for the whole assembly. The advantage of this method is that it can also be used when the permittivity of the material housing the liquid is not accurately known.