EM susceptibility studies and measurements on electro explosive devices

Electroexplosive devices (EEDs) are susceptible to stray electromagnetic (EM) fields near high-power communications and radar transmitters. Experiments have been carried out to measure the exact susceptibility of EED resistive squibs in pulsed and continuous EM environments, respectively. The susceptibility test procedure consisted of individual measurements of direct current sensitivity (mA); impulse sensitivity; RF impedance measurements; and safety margin calculations. A stray energy monitor was used to evaluate the safe performance of a hybrid weapons system. It is found that the RF sensitivity of the squib was influenced by the transmission characteristics of the transmission line connected to it. RF absorption peaks were observed above the EED sensitivity threshold of 120 MHz. Methods of EMI control are discussed, including: low-pass pin filters; lossy line filters for all dc power line interconnections; and twisting and shielding of the wires.