Lightning Transient Analysis of Radio Base Stations

Radio base stations (RBS) are composed of antenna systems on a steel tower, radio equipment systems on the ground, and interconnection signal/power cables. They are frequently exposed to lightning strikes. For protection against lightning, modeling such complex systems is always a necessary but tricky task. In this paper, a procedure is presented to model the RBS system. The steel structure that may carry substantial lightning currents during lightning strikes is included in the model. To facilitate time-domain simulations for frequency-dependent conductors, a vector fitting enhanced PEEC method is adopted. In this method, magnetic material, skin effect, and proximity effect are taken into account. Meanwhile, the models of protection circuits at the equipment ports are presented. Their circuit parameters are provided with the data collected from experiments. Laboratory tests on a simplified radio-base-station system are performed. Good agreements with the simulation results are observed. Finally, lightning surges in a practical RBS system are presented.