Research On RCSR Technology Based On The Wave Absorption And Scattering Manipulation Mechanisms

With the development of radar deteetion technology,higher and higher radar eross section(RCS)reduction performance is required for radar stealth technologies.Most of the existing radar stealth surfaces are based on single wave absorption or scattering manipulation mechanism and faced with contradiction between thin thickness,light weight and high stealth performance such as RCS reduction within wide frequency band or wide incident angle.Hence,in this thesis,novel compound radar stealth surface,which combines both wave absorption and scattering manipulation mechanisms for RCS reduction,is proposed and preliminarily investigated for improved RCS reduction performance.In particular,traditional circuit analog absorption(CAA)and anti-phase cancellation are adopted here as the wave absorption and scattering manipulation mechanisms,respectively.The compound radar stealth technology studied in this thesis is constructed by two kinds of reflecting-absorption-mixed elements.These two kinds of elements operate as CAA elements in two different frequency bands and have approximate 180 degree reflection phase difference in the band between the two absorption bands.The whole compound surface hence achieves broadband RCS reduction through wave absorption in the low and high CAA frequency bands,and anti-phase cancellation in middle frequency band.This thesis first designs two pure circuit analog absorbers at different frequency bands.By analyzing and comparing the frequency-dependent reflection characteristics of the constituted elements of the pure CAA designs,the working principle of compound radar stealth surface is promoted.Then a compound radar stealth surface combining two CAA elements are designed for monostatic RCS reduction purpose.The design is performed by optimizing size length and square resistance of resistive patch,and ratio of the two CAA elements.Simulated and measured results confirms the validity of the design and hence the proposed compound RCS reduction mechanism combining circuit analog absorption and anti-phase cancellation.Finally,an improved compound radar stealth surface with double periods for bi-static RCS reduction purpose is further designed.The improved design is accomplished by optimizing not only the ratio,but also the arranging sequence of the two CAA elements.