Analytical results have been derived for the lossless infinite parallel‐plane waveguide inhomogeneously loaded with a ferrite‐dielectric composite medium. It is found that the existing mode is a hybrid mode composed of all six field components. The magnetic property of ferrite in this composite medium is masked by the presence of a dielectric. It has been shown that this study represents a good approximation for the complicated microstrip transmission lines fabricated out of this composite medium.