The electromagnetic field in an EMP simulator at a high frequency

The electric field in the working volume of an EMP simulator has been determined experimentally in both amplitude and phase at a frequency that is high enough so that the simulator no longer behaves like a terminated-TEM-mode transmission line. Graphs of the field in the working volume are displayed and interpreted in terms of the TEM and higher parallel-plate modes. The actual field is shown to differ greatly from that characteristic of the TEM mode so that it must be expected that current and charges induced on an obstacle are also very different from those that would be observed if the excitation were an incident plane wave.