Crosstalk and electromagnetic interference noise investigation for a coupled pair of microstrip lines with a break in ground structure

A simple approach has been proposed to determine parameters of coupled pair of microstrip lines (CPMLs) with break in ground structure. A break or slot in the ground plane raises the impedance of microstrip lines. Firstly, the S-parameters of the transmission lines are obtained using an electromagnetic simulator. Then the L and C values are extracted using circuit modelling approaches. Measurements were performed using a vector network analyser for the fabricated CPMLs. Results show that the parallel or crossed break with decoupling capacitors or ferrite beads enhances the noise isolation and lead to a reduction of signal reflection and the radiated emission. Frequency characteristics such as crosstalk, return loss and electromagnetic interference radiated noise in the crossed break are degraded if capacitors or beads are not used.