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《地面、沙漠的電磁散射特性研究》由會員上傳分享，免費在線閱讀，更多相關(guān)內(nèi)容在學(xué)術(shù)論文-天天文庫。
1、摘要摘要本文首先給出了粗糙面散射的基本理論，給出了隨機粗糙面和沙丘的生成方法，介紹了粗糙面散射的基本方法基爾霍夫近似和微擾法；給出了沙漠的縱向沙丘和橫向沙丘散射模型，推導(dǎo)了沙丘間多次散射的后向散射系數(shù)公式并分析了隨波長、介電常數(shù)、高度均方根、相關(guān)長度和散射系數(shù)角分布的變化，與雙尺度計算結(jié)果進行了比較。利用四成分模型計算了土壤濕度與土壤介電常數(shù)的關(guān)系，并分別用基爾霍夫近似法和微擾法計算了考慮不同土壤類型的電磁散射?；诨鶢柣舴驑?biāo)量近似法和駐留相位近似法研究了粗糙面下方介質(zhì)中的電磁透射和散射，導(dǎo)出了不同極化狀態(tài)下
2、指數(shù)譜粗糙面透射系數(shù)計算公式并進行了數(shù)值計算和討論。最后利用微擾法計算了分層地面模型的一階散射場，對其進行了詳細討論并與單層模型的散射系數(shù)進行了比較。關(guān)鍵詞：粗糙地面，沙漠，電磁散射，微擾法，分層粗糙面，透射系數(shù)AbstractInthisthesis，fundamentaltheoryofelectromagneticscatteringfromtheroughsurfaceiSintroducedforrandomroughsurfacemodelsandelectromagneticscattering
3、models，suchaSKirchhoffApproximationandSmallPerturbationApproximation．Modelsoflongitudinalduneandtransverseduneonthedesertarepresented．Backscatteringcoe伍cientofmultiplescattenngbetweendunesisderived．neinfluencesofwavelength，dielectricconstant,meansquareroot,
4、correlationlengthandslopeangularonthescatteringcoefficientfromtheroughsurfaceswithExponentialspectrumareanalyzed,andnumericalresultsarecomparedwithTwo—ScaleModelfordifferentdesertmodels．Accordingtothefour-elementmodel，therelationbetweenhumidityanddielectric
5、constantofsoiliSpresentedandelectromagneticscatteringfromsoilsurfaceiscalculatedatdifferentsoilsbyKirchhoffandSmallPerturbationMethod．BaSedonScalarApproximationandStationary—PhaseApproximation,electromagneticscatteringandtransmissioninthemediumunderroughsur
6、faceareinvestigatedandformulaeoftransmissioncoefficientsfordifferentpolarizationsarepresentedanddiscussednumerically．111ediagramofthescatteringcoefficientfordifferentpolarizationtransmissionwaveconsideringExponentialspectrum、析mvaryingofthescatteringangle，th
7、escatteringazimuthangleandthefrequencyoftheincidentwaveisobtainedbynumericalimplementation．Finally,thefirstorderelectromagneticscatteringfromlayeredmodelroughsurfacesisalsoexaminedbyapplyingtheSmallPerturbationMethodandthecomparisonofscatteringcoefficientsf
8、orthelayeredmodelandsurfacereflectionaregivenanddiscussedindetail．Keywords：Roughlandsurface，Desert，Electromagneticscattering,SPM，Layeredroughsurface，TransmissionCoefficient創(chuàng)新性聲明本人聲明所呈交的論文是我個人在導(dǎo)師指導(dǎo)下進行的研
