Research And Design Of Beam Deflection Maface Antenna

With the development of unmanned vehicle technology,unmanned aerial vehicle technology and intelligent transportation technology,obstacle avoidance technology of sports platform has attracted extensive attention from academia and industry.Typical crash-avoidance technologies include microwave radar,lidar,optical vision and ultrasonic radar.Millimeter-wave obstacle avoidance radar has become one of the most promising obstacle avoidance means because of its advantages of high precision,miniaturization,low power consumption and all-weather adaptability.MMW obstacle avoidance radar is mainly composed of transceiver antenna,rf front-end circuit and backend signal processing module.As the antenna is located at the front end of the system,it is responsible for transmitting electromagnetic signals and receiving echo signals,whether the index is good or not relates to the overall performance of radar.Therefore,this topic focuses on the research and design of the microstrip array antenna and beam deflection technology on the millimeter wave obstacle avoidance radar of UAV.Firstly,this paper analyzes,summarizes and compares the research background,significance and current situation at home and abroad.On this basis,the research and design methods of millimeter wave microstrip antenna and metamaterials are systematically studied.According to the antenna design theory,this paper studies and designs a kind of 77 GHz millimeter-wave transceiver microstrip array antenna based on the index requirements of MMW radar proposed by UAV obstacle avoidance technology.The antenna consists of a transmitting array and two receiving array,the array composed of 44 rectangular radiating element,launch direction gain of 31.21 dB,launch E plane and H plane of figure 3dB beam width is 9.25° and 9.34° respectively,sidelobe level is-21.69 dB and-20.47 dB,standing wave ratio less than 2.Because of the characteristics of high gain,narrow beam and low sidelobe,the transmitting antenna can meet the requirements of detection range,Angle resolution and signal-to-noise ratio.In order to realize the measurement of azimuth Angle,the system uses two receiving antenna,receiving antenna radiation by 12 units in the form of a two-dimensional array,with the gain of 16.46 dB,direction of E plane and H plane 3dB beam width of 36° and 13.98° respectively.In addition,in practical application scenarios,the complex flight environment also puts forward requirements for the detection of UAV lateral obstacles.In order to avoid the interference of the frame and rotor to the detection,the side obstacle avoidance radar is also required to be installed in the front of the UAV.In order to ensure the compact structure,this paper designs a beam deflection antenna loaded with metasurface material,which is composed of three dielectric plates.The microstrip antenna unit is located on the bottom dielectric plate,and one metamaterial unit is placed on the top two dielectric plates.According to the beam inclination theory,a metamaterial structure unit with a working frequency of W band and a bandwidth of 75GHz-79 GHz was designed.The metamaterial structure was optimized by electromagnetic simulation,and the beam deflection antenna loaded with double-layer metamaterials was obtained.The simulation results show that the microstrip antenna can implement 48° deflection of the beam,and the gain was 34.6% higher than that without metasurface material.