Guided-wave characteristics of coplanar waveguide metamaterials composed of unsymmetrical unit cells

Transmission line metamaterials on CPW with unsymmetrical unit cells, loaded by series- C and shunt-L elements, are studied to demonstrate the distinctive characteristics of incident and reflected guided-waves. Two sets of per-unit-length transmission parameters, i.e., propagation constant and Bloch-wave impedance, are numerically extracted using our self-calibrated method of moments and they are illustrated in the frequency range, covering the LH stopband, LH passband, LH/RH stopband, RH passband and so on. It is exhibited in theory that this unsymmetrical CPW metamaterial has two unequal Bloch-wave impedances associated with two opposite guided-waves. Finite-length CPW structures are then modeled to showcase the propagation performance across these 1-D metamaterials. Two-port 9-cell CPW metamaterial circuit with 50-Omega feeding lines is in final characterized so as to give an evident validation on the predicted guided-wave properties in experiment.