Backward-wave waveguide based on uniaxial anisotropic negative permeability meta-material

A rectangular waveguide filled with anisotropic uniaxial meta-material with negative effective permeability is analysed in this paper. It is shown that such a structure supports propagation of backward wave below the cut-off frequency of an empty waveguide. Thus, the waveguide behaves as a ´backward-wave transmission line´ (or ´left-handed transmission line´). Two experimental rectangular waveguides loaded with split-ring resonators in 10 GHz frequency band have been designed, fabricated and tested. The measured results revealed backward-wave pass-band located below the cut off frequency. It was also shown that the increase of physical length of the waveguide caused the decrease of the electrical length. This is the proof of backward-wave propagation since the phase of backward wave increases along the waveguide.