Per-unit-length parameters of 1-D CPW metamaterials with simultaneously series-C and shunt-L loading

CPW transmission line metamaterials with simultaneous loading of series-C and shunt-L lumped elements in periodical intervals are thoroughly investigated using a self-calibrated method of moments (MoM). Two effective per-unit-length parameters, i.e., propagation constant and characteristic impedance, are numerically extracted to demonstrate the complete guided-wave characteristics of these 1-D artificial metamaterials in a wide frequency range, covering the LH stopband, LH passband, LH/RH stopband, RH passband and so on. In the LH passband, the phase constant with negative sign rises up to zero with the frequency while the characteristic impedance with only non-zero real part goes up from zero and then falls down beyond peak. Under perfect impedance matching in two terminals, finite-length CPW structures are consequently modeled to showcase the transmission performance across these 1-D metamaterials with varied lengths. Finally, a 9-unit cell CPW metamaterial fed by two 50-12 CPW feeding lines is designed, fabricated and measured to validate our reported effective per-unit-length parameters in experiment.