Research On Electromagnetic Metamaterials Applied To Ultra-wideband RCS Reduction

With the rapid development of radar detection technology,requirements for radar stealth technology of modern warfare are getting higher and higher.The key to stealth technology is to reduce the RCS of target carriers(such as fighters,tanks,antenna araay,etc).Using metamaterial is an effective method to reduce the RCS of target carriers.There are many types of metamaterial,including EBG structure,PCM,left-handed material,FSS and so on.This paper is mainly to study the application of EBG structure and PCM in reducing RCS.The main contents are as follows:1.Two patch-type EBG cells are adopted,and the influence of each parameter on the band gap of in-phase reflection is analyzed.The scattered field can be redirected,for the reflection phases of the two types of EBG cells are opposite in their frequency band.Compared with PEC,the RCS of the checkerboard EBG surface can be reduced more than 10 dB from 8.6 to 19.6 GHz,and the randomly arranged EBG array is studied.In addition,loading the EBG structure on the designed microstrip slot antenna can effectively reduce the in-band and out-of-band RCS of the antenna while the radiation performance of the antenna is substantially unchanged.2.On the basis of the existing PCM structure,an improved PCM cell is proposed to realize a wider frequency band of polarization conversion,and the effect of metalic via and the upper substrate is analyzed.Additionally,the mechanism of polarization conversion is expounded by decomposing and synthesising vector,and showing the flow of current on the surface of the patch.With a checkerboard surface of improved PCM cells,the relative bandwidth of 10 dB RCS reduction increases from 98%to 105%.3.In combination with the methods of using metalic via to change the current on the surface of the patch and loading the upper substrate to enhance the polarization conversion,a new type of PCM cell is proposed for the newly-designed metal patch.The 90%polarization The relative bandwidth of polarization conversion rate over 90%and the 10 dB RCS reduction are 110%and 112%respectively.In addition,the new PCM structure is loaded on the microstrip slot antenna to realize in-band and out-of-band RCS reduction,while the radiation perfonnance of the antenna is well maintained.