Compact traveling-wave physical simulator for human ESD

Existing travelling-wave electrostatic discharge (ESD) simulators satisfactorily reproduce the characteristics of a human discharge but have dimensions comparable to a human subject, so they are inconveniently large for practical ESD susceptibility testing of electronic equipment. This paper describes the design of a compact travelling-wave ESD simulator with benchtop-scale dimensions. The design process utilized frequency-domain measurements and computer simulations of wave attenuation on the part of the simulator representing the human arm. From these results, it was deduced that the ESD simulator arm could be shortened from its original human-scale length of 60 cm to a more compact 30 cm without significantly affecting the currents flowing on it. The part of the simulator representing the human body was designed on the basis of capacitance. The resulting travelling-wave simulator (arm and body) is approximately half the size of the original simulator. Measurements are presented comparing the compact simulator with a previously-designed full-size simulator and with a human test subject, with regard to arm currents, swept-frequency input impedance, and capacitance.