Analytical modeling of differential launch structures for RF measurements and characterization purposes

An analytical methodology for characterizing signal launchers for differential microstrip lines is presented in this paper. The methodology is formulated using the modal domain (i.e., differential and common mode) and ABCD matrices obtained from S-parameters measured to two lines differing only in length and terminated with Ground-Signal-Signal-Ground (GSSG) configured pads. Excellent correlation in both the frequency and time domain using the proposed method is achieved when confronted to experimental data up to 20 GHz and for rise times in the order of picoseconds respectively.