A Realistic Description of Mode Propagation in Suspended Coupled Stripline

The effect of finite metallization thickness and mounting grooves on the propagation characteristics of suspended coupled striplines is investigated with a rigorous and versatile hybrid mode analysis. Presented results demonstrate that increasing metallization thickness lowers the propagation constants of both quasi-TEM modes, whereas the propagation constant of the slot mode shows an increasing tendency close to cutoff and a decreasing behaviour well beyond cutoff. It was also found that higher-order modes are strongly affected by the mounting grooves.