An Airborne Radome Protection Design against Lightning direct effects based on Return Stroke Analysis

Lightning strikes can affect avionics operation and security, causing costly service interruptions and even damage. Although the advent of advanced sensors and detection technologies has reduced the probability of lightning strike incidents, it is almost inevitable in the life cycle of an aircraft. Therefore, lightning protection based on the application scenarios and performance requirements of radomes is crucial. In this paper, a lightning protection design is proposed for the airborne radome. With this design, a radome should withstand a Zone1 A level test defined by RTCA/DO-160G, which is widely considered to be most critical for airborne equipment. Starting with the evaluation of lightning strikes on an airborne radome according to return-stroke theory, a radome model with a conformal antenna and mounting bracket is introduced to demonstrate the electromagnetic field and thermal distribution of the radome during lightning discharge. A high-voltage discharge attachment simulation and a large-current destruction simulation are carried out to determine the core factors of airborne radome protection. Corresponding methods on antenna and skin are taken to reduce the potential damage owning to former weak points, including the design of the conformal array and material. A prototype radome with a thickness of 0.8 mm withstands a high-voltage and a large-current test, which demonstrates the design's effectiveness.