Effective 1-D material properties of coplanar-waveguide-based EBG- and meta-materials

This paper aims to give unified characterization of coplanar-waveguide-based 1D electromagnetic-bandgap (EBG) and metamaterial in terms of two fundamental per-unit-length (PUL) transmission parameters, i.e., characteristic impedance and propagation constant. In analysis, a full-wave self-calibrated method of moments (MoM) is applied to de-embedding these two PUL parameters from simulation of two-port finite-extent CPW sections. Firstly, 1-D CPW-based EBG material with periodical loading of series-inductive units is studied to provide a physical insight into slow-wave and bandstop behaviors of guided-wave. Then, CPW metamaterials with simultaneous series-capacitive and shunt-inductive loading are investigated to demonstrate the guided-wave performances in the distinctive left- (LH) and right-handed (RH) passbands. It is demonstrated that the stopband or bandgap between the LH and RH passbands can be wholly eliminated by properly selecting distributed CPW elements. A few CPW circuits based on these 1-D EBG and metamaterials are in final fabricated to confirm the theoretical predictions.