Research on wave transmissivity through bumper based on transmission line model

In order to meet the wave transmissivity requirements of the millimeter wave radar arranged behind the bumper, a model of the wave transmissivity performance of the painted bumper was established based on the transmission line model. Taking the one way attenuation value of the radar signal as the optimization objective, important parameters such as the substrate thickness of the painted cover plate, the film thickness of different paint layers, the relative permittivity, the loss tangent and the incident angle were studied. The simulation and experimental results show that the bumper substrate thickness and silver paint with high relative dielectric constant have a key impact on the performance of millimeter wave radar. Considering two layers of paint, the wave transmissivity of the silver bumper decreases obviously. The gradient descent method is used to optimize the bumper substrate thickness. The results show that through the optimization of substrate thickness and tolerance control, the one way attenuation values of bumper are all meets the requirement in the radar signal frequency band.