Practical e-field sensors for EMP testing

The suitability of different electric field sensors compiled from commercially available standard coaxial RF connectors are compared by measuring nanosecond high voltage pulses generated by an EMP simulator. The EMP simulator is a parallel-plate transmission line connected to a high voltage pulse generator capable of producing 2-5 ns risetimes and voltages up to 100 kV. The propagating electric fields produced in this research are approximately 50 kV/m along the parallel portion of the transmission line. The electric field sensors are essentially very short monopole antennas. The output of the sensors (D-dot probes) is the first derivative of the incident electric field and requires integration to yield the final waveform. The investigated sensors include 12 different variations of ground plate mounted SMA, BNC, UHF and N type coaxial connectors with bandwidths ranging from 0.2 - 18 GHz. The reliability of the constructed electric field sensors is verified using magnetic field sensors. Despite the largely diverse characteristics of the sensors, their outputs are rather consistent indicating that all of the selected sensors are equally applicable for measuring ns-range pulses.