Research On 24GHz Vehicle-Mounted Radar Antenna Based On Fractal Theory

Considering many factors such as vehicle intelligence and safety,antenna is the main part of vehicle radar system,and its size,structure and radiation performance play an important role in the system performance of vehicle radar.As a short-range detection radar,24 GHz antenna can be used in reversing assistance,blind spot detection,automatic parking and so on.Based on the fractal theory,this paper mainly analyzes and designs the miniaturized broadband vehicle-mounted radar antenna applied to 24 GHz.A two-layer miniaturized wideband antenna is designed by using Minkowski fractal theory.The fractal structure of the upper radiation patch is used to accurately control the resonant frequency of the antenna,and the purpose of miniaturization is achieved.The impedance bandwidth of the final control antenna is 23.59GHz-24.46 GHz,and the gain is 7.32 d B.In order to realize dual frequency,the upper and lower radiation patches were fractal at the same time,and the frequency was controlled by the change of size and size.The two-layer Sierpinski fractal antenna structure is analyzed and designed.The results show that when the upper dielectric substrate is higher than the lower substrate,it is more conducive to the excitation of electric field radiation.In the four-parasitic patch antenna designed by the defective structure,the size of the main radiation patch is 1.821mm×3.25 mm,and the working bandwidth is 23.45GHz-24.55 GHz.By combining Minkowski and Sierpinski fractal theory and improving the iterative method,a fractal double-layer antenna is designed,which can make the antenna achieve miniatization and maintain the relative stability of gain,and the bandwidth is greater than 1GHz.The maximum gain of the antenna in the 1×4 array is 12.37 d B and the sidelobe level is low.