(a) Topology of the unit cell of a CPW CRLH transmission line based on a combination of series connected OSRRs in the external stages and a pair of shunt-connected OCSRRs in the central stage; (b) frequency response; (c) characteristic impedance; (d) dispersion diagram. The considered substrate is the Rogers RO3010 with thickness and dielectric constant . Dimensions are and . For the open complementary split ring resonator: and . For the open split ring resonators: . From [16]; copyright © 2009 IEEE, reprinted with permission.