Dual Composite Right-/Left-Handed Coplanar Waveguide Transmission Line Using Inductively Connected Split-Ring Resonators

In this paper, a simple geometrical modification of the well-known split-ring resonator (SRR) topology is proposed. This modification consists of joining the opposite sides of the rings by means of an inductive connection. Due to this modification, it is possible to synthesize a dual composite right-/left-handed artificial transmission line from a host coplanar waveguide (CPW). In addition, it is quite straightforward to synthesize a dual balanced line showing a wider transmission bandwidth (around 13% for 3 GHz and 8% for 6 GHz) with this new SRR geometry. In fact, in order to design a balanced line, one must just modify the inductance of the direct connection between the rings, which can be derived from the equivalent circuit of this new ring, which is also presented in this paper. The final result is a balanced artificial CPW transmission line with a dual composite right-/left-handed behavior. In this case, the right-handed transmission band is placed below the left-handed one, and there is no frequency separation between both transmission bands.