Research On Optimization Method Of Low Sidelobe Arc Array Antenna

Compared with conventional linear array antennas,the arc array antennas break through the limitation of a single observation angle,and realize real-time,omni-directional,highresolution,and large-field observation of the surrounding environment.Simutaniously,the front of the arc array antenna can be installed on the surface of the flying carrier,so that the antenna aperture and scanning range of the radar can be expanded,and the aerodynamic influence of the radar observation platform can be reduced,which makes up for the shortcomings of the traditional array.The sidelobe level is one of the important indicators of a radar antenna.High side-lobe level is easy to reduce the antenna efficacy and the quality of received signal.This thesis mainly studies the optimization method of low sidelobe arc array antenna.The main contents are as follows :The thesis first introduced the basic theory of the array antenna,deduced the pattern function of the uniform linear array and the arc array,and completed the simulation and analysis of the radiation pattern of the arc array antenna.The integrated process of the arc array antenna pattern is shown by the aperture projection method.On this basis,an optimal design method of arc array antenna based on genetic algorithm is proposed.Firstly,the directed array element is introduced.Secondly,based on the fitness function optimization model,the amplitude and phase weights are optimized by the method of increasing the population diversity in the three ways of amplitude,phase,and amplitude-phase combination.Finally,the result of the sidelobe level reduction of the arc-shaped array antenna is obtained.The simulation experiment results show that the combined amplitude-phase optimization method is more conducive than the realization of the low sidelobe of the arc array antenna.Aiming at the sparse optimization problem of low sidelobe arc array antennas,an improved discrete cuckoo optimization algorithm is proposed.The algorithm mixes the Levy flight mapping function with the encoding of the discretized nest position,and introduces binary encoding control coefficients to reduce the sidelobe level of the arc array.Simulation experiments show that the algorithm takes into account the fast convergence performance while maintaining the global search ability,and verifies the effectiveness and correctness of the method.Aiming at the problem of gain reduction of the main lobe of the sparse arc array antenna,a method of increasing the gain of the arc-shaped array based on filling a high dielectric constant medium was proposed and a W-band high-gain waveguide array antenna was designed.If the arc array antenna is filled with a medium with a high dielectric constant,the main lobe gain is increased to 1.81 d B.After being sparsely optimized,the gain of the main lobe of the arc array antenna is increased to 1.43 d B,and the sidelobe level is reduced to-22.58 d B,which meets the design requirements of the low-sidelobe and high-gain arcshaped array antenna.On this basis,the physical processing and testing of the arc array antenna sub-array have been completed,and the test results verify the design method in this thesis,which have certain practical engineering application value.