Simulation computation and analytic modification of characteristic impedance of parallel-plate transmission line

Based on time domain reflection theory, a novel way to calculate the characteristic impedance of a parallel-plate transmission line is proposed. With CST microwave studio, a simulation model is established to calculate the accurate value of the characteristic impedance of the parallel-plate transmission line. Based on the results, the analytic formula for the characteristic impedance of the parallel-plate transmission line is modified. Furthermore, the effect of broadening of the bottom plate of parallel-plate transmission line on its characteristic impedance is researched. Considering the effect of broadening of bottom plate, a new formula for the characteristic impedance of the parallel-plate transmission line is proposed. The final formula could be applied to the calculation of the characteristic impedance of bounded-wave simulators and other electromagnetic pulse simulators with similar structure.