Double Periodic Composite Right/Left Handed Substrate Integrated Waveguide

A double periodic composite right/left handed (DP-CRLH) transmission line (TL) is proposed based on the TL theory. In addition to the composite right/left handed property, a new leaky-wave radiation is observed below the left-handed passband. The equivalent circuit of the proposed structure is analyzed, and dispersion characteristics are investigated by changing the ratio of the loaded alternative inductances. Substrate integrated waveguide (SIW) implementation of a DP-CRLH TL is designed and illustrated with simulated and experimentally demonstrated results. The radiation patterns demonstrated the DP-CRLH SIW exhibits the expected forward radiation at the new leaky-wave region.