Evaluation of discontinuities in microstrip transmission lines by picosecond time domain reflectometry technique

The narrow and wide trace discontinuities in microstrip transmission lines are designed and fabricated on glass-epoxy board by standard printing circuit board (PCB) technology, These discontinuities are characterized by evaluating their characteristic impedance (Z(0)), excess inductance (DeltaL), excess capacitance (DeltaC), and peak percent reflection (rho(max)), by single ended time domain reflectometry (TDR) technique at room temperature. It is observed that narrow trace discontinuities lead to increase in values of characteristic impedance and inductance while wide trace discontinuities lead to decrease in characteristic impedance and capacitance. The experimental values of various parameters like characteristic impedance, Z(0), excess inductance, DeltaL, excess capacitance, DeltaC, and maximum peak reflection, rho(max), are found to be In good agreement with their corresponding theoretical values.