A Novel Metamaterial Transmission Line With Adjustable Left-Handed Elements and Its Application to $H$ -Plane Filter

This letter presents a metamaterial transmission line (TL) with enhanced designing flexibility. Interdigital fingers and rectangular slots are etched on the top and bottom metal plates to generate series capacitances and shunt inductances, respectively, which give rise to the composite right-/left-handed (CRLH) property. In this structure, the rectangular slots provide adjustable shunt inductances that facilitate the design of CRLH property compared with that in previous work. Furthermore, the increment of the shunt inductances also enables more compact size due to lower resonance. Examples are given to verify the advantages by comparing the dispersions, S-parameters, and extracted values of lumped elements for two types of CRLH TLs with various physical dimensions. In addition, a bandpass filter is implemented by the proposed CRLH TL with partial H-plane coupling structure. The filter is fabricated and measured, and the result shows a good agreement between the measurement and simulation.