CRLH waveguide with air-filled double-ridge corrugations

A rectangular waveguide periodically loaded with air-filled short-circuited double ridge stubs is proposed as a composite right/left-hand guided-wave structure. The proposed structure uses the fact that double-ridge waveguides have lower cutoff frequencies as compared to rectangular waveguides with the same width. Parametric study is made on the various design parameters to investigate their effect on the LH propagation.