Application of anisotropic EBG for suppressing common-mode resonances in CPW-to-CPS transitions

The phenomenon of common-mode radiation limits the in-band performance of balanced transmission lines such as the coplanar strip (CPS). When such transmission lines are measured single-endedly, by connecting them between practical baluns/transitions, resonances in the frequency response are observed owing to common-mode propagation. It is proposed, and demonstrated for the first time, that an electromagnetic-bandgap ground (EBG) method can help to suppress the unwanted propagation of common-modes along balanced transmission lines.