Group delay characteristics in coplanar waveguide left-handed media

We present a combined theoretical and experimental study on the group delay behavior of four coplanar waveguide structures loaded with pairs of split-ring resonators (SRRs) and strip lines (SLs). These structures are effective left-handed media, which are designed to operate at S-band frequencies. For one and three pairs of SRRs/SLs full-wave simulations predict a maximum negative group delay of −3.9 and −7.9 ns, and a bandwidth of 160 and 150 MHz, respectively. Experimentally we find a group delay of −4.7 and −8.5 ns and a bandwidth of 190 and 290 MHz, respectively. Surprisingly, we do not observe a negative group delay if the structure contains an even number of SRRs/SLs pairs. Yet, the structures with an odd number of pairs may be used to control the dispersive effects for a variety of systems. Further, we discuss the group delay in the pass band as these structures may also be used as filters.