Modelling of an electromagnetic pulse simulator and evaluation of its radiated field

The detonation of a nuclear device in or above the atmosphere is known to produce fast varying strong electromagnetic field signals called nuclear electromagnetic pulses (NEMP). The most well known type of such simulator in a laboratory is the parallel plate simulator (PFS). For the purpose of analysis, the parallel plates of such a simulator have been modelled as a transmission line applying microstrip design concepts. To understand the effect of the stripline and also to ensure proper impedance matching between the impulse generator and the stripline, the various parameters are simulated using PSpice. Although the behaviour of the electric field (E-field) and the magnetic field (H-field) within the working volume of the simulator is well understood, little attention has so far been paid to determine the field induced in the equipment under test (EUT) region and the radiated fields. These have been evaluated by solving Maxwell's equations applying the finite difference time domain (FDTD) method with appropriate boundary conditions.