Electromagnetic pulse simulators are essential for testing the ability of electronic devices to withstand high intensity electromagnetic ends. This work presents the analysis of various parallel plate transmission lines used in electromagnetic pulse simulators. Numerical techniques are developed to obtain the characteristic impedance, field map, and cut-infrequencies for the higher order modes of these transmission lines as exact analytical methods are not available for the determination of these quantities. The field map and characteristic impedance are computed using both finite element method (FEM) and boundary element method (BEM). Cut-off frequencies of the higher order modes are computed using FEM. The analysis presented can handle very general transmission line geometries. This analysis is useful for the design of electromagnetic pulse simulators.