双负媒质宽频电磁散射特性分析 毕业论文

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1、双负媒质宽频电磁散射特性分析摘要近年来，双负媒质材料的研究成为研究合成材料的热点。鉴于其异于传统媒质的典型特性，其应用十分广泛。在信息化的今天，快速计算双负媒质散射体的电磁散射特性，对实现双负媒质的宽频带的电磁散射特性分析很有现实意义和价值。本文首先介绍双负媒质的研究背景与意义。然后介绍PMCHWT方程推导过程和矩量法的基本理论，阐述渐近波形估计技术的基本理论。最后从双负媒质的本构关系出发，应用电磁辐射理论，推导出双负媒质的PMCHWT方程，从而解出单频率入射波下的电流和雷达散射截面。由于双负媒质的阻抗元素是波数的复杂函数，对阻抗元素进行直接

2、求导、而高阶求导却无法实现，因此利用组合以及复合函数的求导思想实现了阻抗元素高阶导数的求导，将渐近波形估计技术应用于双负媒质的宽频电磁计算领域。计算实例结果表明，渐近波形估计技术不仅在感兴趣的频段内能很好逼近矩量法逐点求解的结果，而且在计算效率上也大大提高。关键词：双负媒质；雷达散射截面；渐近波形估计；Drude模型；PMCHWT方程。ABSTRACTInrecentyears,theresearchofdoublenegative(DNG)meta-materialbecomesoneofthehottesttopicsincomposit

3、ionmaterials.Basedonitstypicalcharacteristicsdifferentfromtraditionalmaterials,theapplicationofDNGmeta-materialisverywide.Followingthedevelopmentofinformationtechniques,rapidcomputingdoublenegativemediumscatteringtheelectromagnetismscatterofbodycharacteristicandtherealizati

4、onofdoublenegativemediumtheelectromagneticscatteringofbroadbandisverypracticalsignificanceandvalue.Thispaperfirstintroducestheresearchbackgroundandsignificanceofdoublenegativemedium.ThenintroducetheprocessofPMCHWTequationderivationandtoexplainthebasictheoryofmethodofmoments

5、andasymptoticwaveformevaluationtechnique.Finally,fromthedoublenegativemediaontheconstitutiverelation,applyelectromagneticradiationtheorytodeducethePMCHWTequationofdoublenegativemedium,thussolvethecurrentandtheradarcrosssectionunderthesingle-frequencyincidentwave.Owingtothei

6、mpedanceelementofdoublenegativemediumisthecomplexfunctionofwavenumberandthehigherorderderivativeofimpedanceelementcannotachievedirectly,usingtheideologyofcombinationalandcompositefunctionstorealizeit,asymptoticwaveformevaluationtechniqueisappliedtothebroadbandelectromagneti

7、ccomputingrealmofdoublenegativemedium.Theresultsoflivingexamplesofcalculationshowthatnotonlyasymptoticwaveformevaluationtechniqueiseasytoapproachthepoint-by-pointsolvingofmethodofmomentintheinterestedbandoffrequencybutalsothecomputationalefficiencyisimprovedenormously.Keywo

8、rds:Double-Negativemedium;RadarCrossSection;AsymptoticWaveformEvaluation;Drudemode