Numerical prediction and measurement of ESD radiated fields by free-space field sensors

This paper describes the evaluation of electric and magnetic fields due to electrostatic discharges (ESDs) using an efficient numerical prediction model and measurements obtained with simple field sensors. The numerical prediction model is implemented using software based on the finite integration technique (FIT). The ESD generator is efficiently modeled, and the contact-mode discharge current is well reproduced taking into account the loading effect of the generator. Simple free-space field sensors are effectively used to measure the fields from an ESD event. Suitable numerical and theoretical characterizations of these sensors are proposed to derive a sensor transfer function that permits the fields to be reconstructed from the measured voltage. The numerical characterization is performed by Microwave Studio (MWS), while the theoretical characterization is based on lumped element circuit models of the sensors. The validation of both the proposed procedures indicates good accuracy up to 2 GHz as required by the International Electrotechnical Commission standard for ESD measurements.