Induced currents due to nearby lightning strike to a mobile radar system: an hybrid 3D/circuit analysis

The presence of a lightning protection system for mobile radar structure requires a detailed study of the electromagnetic effects due to a nearby lightning strike. Aim of this work is the evaluation of: the induced surface currents on the antenna unit, the currents flowing through the slip-ring (electro-mechanical part connecting the rotating part of the antenna with the fixed one) and the associated dissipated energy, the currents and voltages across the grounding conductors connecting the different units of the mobile radar system. A three dimensional full wave electromagnetic analysis is performed to characterize the induced currents on the antenna unit. This unit is the transformed in an equivalent voltage source. This circuit element is connected to the equivalent circuit model of the grounding cables and rods of the other units to compute the required electrical variables.