Research On High Frequency Superdirectivity Of Receiving Antenna Array For Island

High frequency surface wave radar in shortwave band(3~30MHz),depending on the vertical polarization electromagnetic wave can propagate along the surface of the sea and sea water,low altitude targets over the horizon detection,so hot with its excellent characteristics becomes the research.However,high frequency surface wave radar wavelength in short wave band,corresponding to the antenna array area is often large,when the radar in the construction of the island,the limited place is a problem can not be ignored,we need to carry out the research work of miniaturization.This paper focuses on the miniaturization of HF ground wave radar and the error correction after array miniaturization.On the basis of antenna array error correction,the coherence compensation of each receiving channel is carried out.For the miniaturization of antenna arrays,the thesis firstly studies the superdirective array,gives two kinds of antenna array direction algorithm: the maximum directivity synthesis method of optimal two type synthesis meth od and improved,will exceed the direction of circular array and ordinary circular array for comparison,through the simulation feasibility direction algorithm.For the problem that the efficiency of the over directional array is too small,this paper pres ents the application conditions of the super directional array,that is,the radar system must satisfy the external noise dominant,which provides the basis for the miniaturization of our antenna array.The modeling of 5,7 and 9 element round array is carried out,and the minimum radius of each round array is obtained under the condition of satisfying external noise dominance by means of CCIR data.Finally,the synthesis of super directional circular array is designed.When the antenna is miniaturized,the array spacing becomes smaller,and the influence of mutual coupling between elements will increase dramatically.To solve the mutual coupling error correction of super directional circular array,the influence of mutual coupling error on the array pattern and arrival angle estimation is studied by using the 5 element super directional circular array as the model.In this paper,two kinds of mutual coupling error correction algorithms are proposed: equivalent circuit method and genetic algorithm,and the mutual correction effect of two kinds of correction algorithms is analyzed.Finally,the simulation results of the two algorithms are given.Finally,considering the comprehensive requirements of radar resolution of directivity,and signal-to-noise ratio,we design an array: each super directional circular array as a unit,a plurality of the unit intervals into uniform linear array.The amplitude and phase errors are corrected by the mutual coupling correction and the phase and amplitude error correction of the over direction array.According to the measured data of high frequency ground wave radar amplitude and phase error correction algorithm to verify the feasibility,and are based on amplitude and phase correction algorithm processing radar data,and finally consistency compensation for each receiving channel.