Research On Aperiodic Wide-angle Scanning Phased Array Antenna With Low Sidelobe Levels

Phased array antennas have flexible beam scanning and good anti-interference ability,which have been widely used in 5G communication and vehicle radar communications.Traditional phased array antennas with small scanning angles can not capture information from wide airspace range.Meanwhile,when the antennas scan the near the end-fire direction,the phenomena of high sidelobe levels?SLLs?and even grating lobes will appear,which strongly interferes with the main lobe receiving signal.These problems severely restrict the development of phased array antennas.Therefore,in order to solve these problems and improve the scanning performance of the phased array antennas.This thesis has carried out a series of studies around the wide-angle scanning phased array with aperiodic and low SLLs,the main contents are as follows:The first chapter introduces the research status and significance of wide-angle scanning phased array antenna and aperiodic array antenna.At the same time,several methods for implementing wide-angle scanning and designing aperiodic arrays for phased array antennas are reviewed,and the advantages and challenges of aperiodic wide-angle scanning phased array antennas are analyzed.The second chapter describes the beam scanning principle of phased array antenna and the working principle of genetic algorithm in detail.In addition,the theoretical basis for designing aperiodic phased array based on genetic algorithm is introduced,which provides theoretical support for the design of aperiodic wide-angle scanning phased array antenna with SLLs.In the third chapter,two one-dimensional aperiodic wide-angle scanning phased array antennas with low SLLs are introduced.Firstly,a wide-beam antenna element is constructed based on substrate integrated waveguide slot antenna.Next,genetic algorithm is used to optimize the arrangement of aperiodic array to reduce SLLs during the array scanning process.Finally,a one-dimensional aperiodic wide-angle scanning phased array antenna with low SLLs is constructed.The scanning angle of the phased array antenna has been effectively expanded,and the SLLs are always below-11.2dB during the scanning process.On the other hand,in order to broaden the working bandwidth of the above phased array antenna,a wide-bandwidth beam antenna element is designed with the metal cavity.The array arrangement optimization algorithm is adjusted to obtain a aperiodic array arrangement with lower SLLs.In the fourth chapter,a two-dimensional aperiodic wide-angle scanning phased array antenna with low SLL is introduced.Based on hybrid the microstrip patch TM₁₁ and ZOR modes,a two-dimensional wide beam element is constructed.Using the above element,an 8×8 two-dimensional uniform planar array antenna is constructed,which can achieve wide-angle scanning in two orthogonal azimuth planes and has good SLLs.In order to reduce the SLLs of the array,the element has been miniaturized.The miniaturized element is arranged along the x-axis and y-axis with one-dimensional aperiodic arrangement,and an 8×8 two-dimensional aperiodic planar array is constructed.The phased array antenna can achieve wide-angle scanning in two orthogonal azimuth planes,and the SLLs are always lower than-10dB during the scanning process.Finally,using ideal point sources and a multi-objective genetic algorithm?NSGA-II?to design an 8×8two-dimensional aperiodic array arrangement with low SLLs.The SLLs of aperiodic array are always below-15dB during scanning process.But the space between the elements is too small,this arrangement is only suitable for ideal situations.The final chapter summarizes the above work of this thesis and puts forward the topics that need to be studied in the future.