Study On Effect Of Antenna Cross Polarization On Radar Anti-jamming

The increasingly complex electromagnetic environment has brought great challenges to the detection capability of radars.The interference is no longer the single-polarization interference.Nowadays,the jammer usually generates interferences with different polarization modes.As a result,when the interference polarization changes,the antenna cross polarization may cause the failure of conventional anti-jamming methods.Therefore,it is of great significance to study the effect of the antenna cross polarization on radar anti-jamming technique.This paper mainly focuses on the influence of antenna cross polarization on polarization anti-mainlobe jamming and spatial adaptive filtering.The whole contents can be summarized into the following two parts:1.Effect of antenna cross polarization on polarization anti-mainlobe jamming.First,the basic theory of radar polarization is introduced,which lays the foundation for subsequent research.Then,the algorithm of the polarization mainlobe jamming suppression is studied.The core concept is making the polarization of the filter orthogonal to that of the interference.Finally,we study the influence of the polarization estimation error caused by the antenna cross polarization on polarization anti-mainlobe jamming.Filtering the true polarization is usually done with a polarization calculation filter vector with polarization estimation error.Different from the traditional analysis,this paper evaluates the performance of the polarization anti-jamming using three factors: the true polarization of the incident wave,the output polarization,and the estimated polarization,and argues that small polarization estimation error is compensated in the polarization filter vector calculation section.2.Effect of antenna cross polarization on spatial adaptive filtering.When the interference polarization mode is invariant,the antenna cross polarization leads to fixed inconsistency in the amplitude and phase errors between the array elements,which has less influence on spatial adaptive filtering.But when the interference polarization mode is inconstant,this inconsistency will change,and the impact is serious.First,the basic concepts and principles are introduced,including the signal model and the basic beamforming methods.Then,we introduce adaptive beamforming algorithm,adaptive sidelobe canceller and sidelobe blocking technique.Based on the basic condition that the interference polarization method is inconstant,we study the effect of antenna cross polarization on these three kinds of spatial filtering techniques.The research angles are the change rate of the interference polarization mode and the relationship between the interference polarization mode and that of the antenna.Finally,to eliminate the effect of antenna cross polarization on sidelobe canceller and sidelobe blocking,the main channel antenna is designed as a horizontally polarized omnidirectional antenna and the auxiliary channel antenna is designed as a dual polarized omnidirectional antenna,which contains horizontal and vertical polarization mode.