A mode matching analysis of rectangular dielectric discontinuities in metal waveguides applicable to characterisation of liquids

In this paper we present a generalised scattering matrix approach using mode matching to analyse a generic case of a rectangular dielectric sample and sample holder partially filling a metal waveguide; as encountered in liquid measurements. The results for both samples having real and complex permittivity values, for varying sample thickness are presented and compared to that obtained by a commercial finite element method software.