Slow wave propagation in generalized cylindrical waveguides loaded with a semiconductor

For a parallel-plate waveguide and a microstrip line loaded with a semiconductor slab of resistive or active character, the complex propagation constant γ is determined. γ is found for higher order branches for microwave and millimetre-wave frequencies between 10GHz and 140GHz, representing a very comprehensive study of phase velocity slowing. An assessment of slowing in generalized cylindrical waveguide structures at millimetre-wave frequencies is obtained from this study.