Multiple dielectric structures to eliminate moding problems in conductor-backed coplanar waveguide MIC´

A conventional conductor-backed (grounded) coplanar waveguide (CBCPW) leaks energy from its dominant mode in the form of a parallel plate mode in the substrate region at all frequencies which can generate undesirable coupling effects and produce an ineffective circuit. A multiple dielectric structure with appropriate dimensions is used to suppress the leakage effects and the spectral domain method (SDM) predicts the critical frequency (transition point for leaky and nonleaky modes) for the waveguide. Experimental data verify this procedure and demonstrate the significance of the moding (leakage coupling) problems.<>