Analysis Equations for Shielded Suspended Substrate Microstrip Line and Broadside-Coupled Stripline

Simple and closed-form equations for analysis of shielded suspended substrate microstrip line (SSL) and Broadside-coupled stripline (BSCL) are presented, valid over a practical application range of structural parameters and substrate dielectric constant. Comparing with the values obtained using finite-differential method, the accuracy is found to be within +-2% (w <a/2) and +-3% (a/2<w<a) for SSL and within +-4.5% (odd mode) and +-3.5% (even mode) for BSCL.