A Study on Damage Prediction and Protection of Radar Devices Affected by High Power Electromagnetic Pulse

Abstract

As the threat of electronic warfare increases, many studies have been performed the generation and propagation of high power electromagnetic (HPEM) pulses, and the protection of target systems. Main target of HPEM pulses is communication systems for satellites or radar devices. The HPEM pulse is easily induced to the RF front-end of radars, because the band frequency of radars is the most similar to the frequency of HPEM pulses. Existing studies have mainly performed the experiment by observing the damage points or the simulation by analyzing the thermal distribution of devices, because the power induced by the HPEM pulse is very large and unpredictable. However, the experimental results show only the damaged point after breakdown, and can not explain the damage process by input power level. For protecting electronic devices, it is necessary to predict and analyze how the electronic devices reach to break down. This paper theoretically analyzes the damage process of the low-noise amplifier (LNA) and the band pass filter (BPF) in the RF front-end, and proposes the damage model which can be designed by users in electromagnetic transients program (EMTP). Also, this paper proposes the LNA design to minimize the damage rate by considering both the input conditions of HPEM pulses and the peripheral circuit of an LNA. Lastly, this paper proposes the most suitable protection method considering the intensive care section of the LNA. For the realism of the simulation, this paper considers the amount of the HPEM pulse attenuated by the realistic propagation distance in the medium-tech level. When the attenuated HPEM pulse is coupling to the radar, the maximum induced voltage is used for input source of simulation. As a result, the damage mechanism of the RF front-end affected by HPEM pulses is verified by using the proposed damage model. The damage model can express the all damage processes and show similar results with experiment. The analyzed damage rate and damage model are utilized for protection. The proposed protection using only circuit elements reduced HPEM pulses of medium-tech level to several watt in the simulation. This paper is expected to contribute to the optimal protection technique by predicting and analyzing the damage process of the RF front-end which is the weakest in the HPEM environment.