24 GHz Vehicle Radar Antenna Design

As technology advances,autonomous driving has gradually become a research hotspot in the automotive industry.Autonomous driving technology can improve traffic safety,reduce energy consumption,and decrease environmental pollution.Achieving autonomous driving requires the collaboration of various technologies and devices,such as sensors,controllers,and algorithms.In the field of autonomous driving,antennas play a crucial role as key components responsible for receiving and transmitting wireless signals,enabling information exchange between vehicles and the external environment.Vehicle-mounted radar systems are a technology based on the transmission and reception of radio waves,used for detecting and tracking surrounding target objects,such as other vehicles,pedestrians,and obstacles.Modern vehicle-mounted radar systems have multiple functions,such as adaptive cruise control,collision warning,blind spot monitoring,and automatic parking.Vehicle-mounted radar antennas are key components of radar systems,mainly responsible for transmitting and receiving radio waves.Traditional vehicle-mounted radar antennas mainly include linearly polarized microstrip patch antennas,slot antennas,and horn antennas.However,these antennas have limitations in terms of anti-interference performance,radiation efficiency,and detection range,especially under adverse weather conditions.To address these issues,researchers have recently begun to explore new vehicle-mounted radar antenna designs,such as circularly polarized antennas,phased array antennas,and traveling wave antennas.These new antennas have higher anti-interference capabilities,broader bandwidths,and improved radiation efficiency,thereby enhancing the performance of vehicle-mounted radar systems under various environmental conditions.This study investigates the synthesis and design of low sidelobe series-fed patch antennas.In response to the shortcomings of traditional Chebyshev and Taylor array synthesis methods,this thesis proposes a pattern optimization method based on the Schelkunoff inequality.Through the comprehensive optimization method,a 4 × 8 element low sidelobe series-fed patch array is designed,covering the 24-24.25 GHz frequency band.The antenna gain reaches 20 dBi,and both the E-plane and H-plane radiation patterns achieve sidelobe levels below-20 dB,realizing low sidelobe design in the antenna’s off-axis direction.This validates the advantages of the Schelkunoff polynomial-based array synthesis optimization algorithm in series-fed patch antenna design and achieves excellent low sidelobe performance by combining unequal power dividers with series-fed patch antennas.This thesis investigates a 24 GHz vehicle-mounted radar circularly polarized microstrip traveling wave antenna array design.Compared to traditional designs,this design uses a series-parallel feeding method,simplifying the feeding network and improving the antenna’s anti-interference capability and impedance bandwidth.The matching optimization and axial ratio optimization of the traveling wave unit are discussed in detail,and issues of unstable input impedance and beam shift are resolved through structural improvements and parameter adjustments.Moreover,a circularly polarized traveling wave array design scheme based on terminal radiation loading is proposed,further enhancing energy utilization efficiency and gain.The final design exhibits high gain and good circular polarization characteristics within the range of 24–24.25 GHz,and the simulation results are consistent with the test results,meeting the expected design requirements.