Optimizations for ultra small and wide incident angle metamaterial perfect absorbers at low frequency

ThesisfortheDegreeofDoctorofPhilosophy Optimizationsforultra-smallandwide-incidentanglemetamaterialperfectabsorbersatlowfrequenc y by BuiXuanKhuyen February 2018 DepartmentofPhysicsGrad uateSchoolHANYANGUNI VERSITY ThesisfortheDegreeofDoctorofPhilosophy Optimizationsforultra-smallandwide-incidentanglemetamaterialperfectabsorbersatlowfrequenc y by BuiXuanKhuyen SupervisedbyProfesso rYoungPakLee SUBMITTEDINPARTIALFULFILLMENTOFTHER EQUIREMENTSFORTHEDEGREEOF DOCTOROFPHILOSOPHY AT HANYANGUNIVERSITYSE OUL,SOUTHKOREA February 2018 ©BuiXuanKhuyen,2018 HANYANGUNIVERSITYDE PARTMENTO F PHYSICS December2017 TheundersignedherebycertifythattheyhavereadandrecommendtotheG rad uateSchoolforacceptance a t h e s i s e n t i t l e d " O p t i m i z a t i o n s foru l t r a - s m a l l andw i d e - i n c i d e n t a n g l e metamaterialperfectabsorbersatlowfrequency"byBuiXuanKhuyen in part ia l f u l f i l l m e n t oftherequirementsfortheDegreeofDoctorofPhilosophy ChairmanofCommittee:Prof.JooYullRhee :J-·d ExaminingCommittee:Prof.ChaffwanOh Prof SangJin Sin Prof YoungPak Lee Acknowledgments Iw o u l d l i k e t o t a k e thisopportunitytothankthosep e o p l e : withoutt h e i r h e l p s a n d s u p p o r t s , thisthesiswouldhavenotbeenpossible.Mygreatestthanksmustexpresstomysup erv i sor , ProfessorYoungPakLee,forhisinvaluableguidance,andendlessencouragementoverpast fouryears.Iamveryproudtohavetheopportunitytostudyunderh i s supportsinthisfieldofmetamateri als.My gratitudealsogoestotheq- PsiLaboratory,D e p a r t m e n t ofPhysics,HanyangUniversityforprovidingmeafina ncialsupportintheprofessionalresearchenvironment Iw ou l d l i k e to thankA s s o c i a t e ProfessorV u D i n h La m wh o hase nc o ur a ge d i n myc u r r e n t researches,andDr.NguyenThanhTungwhohasalwayssharedwithmemanyu s e f u l suggestionsandresearchexperiencesinmetamaterials.Itwouldliketoexpressmyd e e p t h a n k f u l n e s s t o ProfessorJ o o Y u l l R h e e a n d ProfessorK i W o n K i m f o r l o t s o f i n t e r e s t i n g discussionsinmystudies.Itisalsoapleasuretothanktheformerandcurrentmemberso ftheqP s i Laboratorya s w e l l a s myfriendsa t H a n y a n g U n i v e r s i t y f o r thef r i e n d s h i p anda llthesupportsinpastfouryears.Inaddition,Iwouldliketothanktomyc l o se friends,bothnewand old,farawayandnearbyfortheircontinuousencouragements,w h i c h arethegreatmotivationsof mylife.Thankyouall Finally,Iowemydeepestgratitudetotheencouragement,thesupport,andthelovefrommyparents, mywifeandmygrandfather I Contents ListofFigures V Abstract IX Introduction 1.1 Historicaloverview 1.2 Frameworkofthethesis .3 Theoreticalbackground 2.1 Materialclassification 2.2 Metamaterialsandeffective-mediumtheory 2.3 Electromagnetic-parameterretrievalfrommetamaterials 2.4 Electricandmagneticresponsesinmetamaterials 11 2.5 Impedancematching 16 2.6 Metamaterialperfectabsorbers 18 Simulationandexperimentofmicrowavemetamaterials 22 3.1 Numericalsimulation 22 3.2 Fabricationtechnique 23 3.3 Measurementconfigurationintheradioband .24 Reducingthesizeofsingle/dual-bandMPAbyincreasingtheeffective inductance of the patterninthe UHFband 26 4.1 Introduction .26 4.2 Metamaterialmodelandfabrication 26 4.3 Mechanismofperfectabsorptionat400MHz .28 4.4 ExaminationonMPAfordifferentincidentradiations 32 II 4.5 Realizationofdual-bandperfectabsorptionviaself-asymmetricstructure 34 4.6 Summary 36 Scaling downthesizeofMPAbyincreasingtheeffective capacitancev i a t h e effective couplingcross-sectionoftopandbottomlayersin theV H F band 37 5.1 Introduction .37 5.2 Metamaterialschemeandexperiment 37 5.3 Physicalmechanismoftheperfectabsorptionat250MHz 38 5.4 Estimationfortheperfectabsorptionatawideobliqueincidentangle .40 5.5 Summary 42 Miniaturizationforsingle/dualbandMPAbyintegratingtheparasiticcapacitorsandthethroughinterconn ectsin theVHFband43 6.1 Introduction .43 6.2 Proposeddesignandmeasurement .43 6.3 Mechanismoftheenergyconsumptionofincomingelectromagneticwaveat102M H z 46 6.4 Investigationontheperfectabsorptionforwideincidentangle 50 6.5 Realizationofthedual-bandMPAbyutilizingsuper-cellstructure 50 6.6 Summary 52 Studyontheminiaturizationfordual/triplebandMPAbyutilizingonlyparasiticcapacitorsintheUHFband 53 7.1 Introduction .53 7.2 Metamaterialmodelandexperimentalsetup .53 II 7.3 Mechanismanalysisoftheperfectdual-absorptionpeakat305and 360.5MHz 54 7.4 Valuationofthedual-bandperfectabsorptionforwideincidentangle 58 7.5 Extendedstudyontriple-bandperfectabsorption 59 7.6 Summary 61 Conclusionsandperspective 62 Listofpublications 66 Bibliography 68 II ListofFigures Fig.2.1Materialclassificationsbasedonsignofεandμμ Fig.2.2DiagramforSparametersmeasurementson(a)ahomogeneous1Dslab(b)aninhomogeneousasy mmetric1Dslaband(c)asymmetricinhomogeneous1Dslab.A singleunitcellofstructureha sathicknessofdμ 10 Fig.2.3 (a)Lattice ofthinmetallicwiresand(b)itseffectivepermittivity(withradiusr=5 mandperiodici tya=40.0mm) 12 Fig.2.4Unit-cellstructureofseveralelectricelements: (a)singleSRR(b)CWand(c)e q u i v a l e n t - c i r c u i t model 13 Fig.2.5Schematicofthemagnetic-resonantelementsas(a)unitcellofCWPstructureand (b)equivalentLC-circuitmodel.SimplifiedLCcircuitmodelsfor(c)magneticand( d ) electricresonantfrequencies,respectively 16 Fig.2 ( a ) Schematico f u n i t c e l l f o r t h e f i r s t M P A ( b ) D i s t r i b u t i o n s o f Ohmica n d dielectriclossesattheresonantfrequency .19 Fig.3.1FabricationprocessofMPAsamples 24 Fig.3.2Schematicofthereflection-measurement 25 Fig.4.1(a)UnitcelloftheproposedMPA.Photosofthefabricated(b)single-peakand(c)d u a l b a nd samples.Insetsin(b)and(c)aretheunitcells, correspondingtothes i n g l e - p e a k andthedual-bandMPAstructures,respectively.(d)Experimentalsetu p forthemeasurement 27 Fig.4.2(a)Simulatedandmeasuredabsorption spectraofthesingle- peakMPA.Redandb l u e dashedarrowsdisplaytheFWHMvaluescorrespondingtothesi mulatedandt h e experimentalabsorptionspectrum,respectively.Inducedsurfacec urrentson (b) thefrontand(c)thebacklayersat400MHz.3-dimensionaldistributionsof(d) themagneticenergy,(e)theelectric energyand(f)thepower lossattheresonantf r e q u e n c y 28 Fig.4 ( a ) E q u i v a l e n t circuito f t h e discussedM P A ( b ) S i m u l a t e d a n d calculateda b s o r p t i o n frequenciesaccordingtothera diusofthequarterofdisk(r)andthew id t h o f slenderw i r e ( w).R e d squareandbluet r i a n g l e symbolsr e p r e s e n t t h e simulatedresults,whilethecalculatedresultsare denoted in blackdotsand greendiamonds 30 Fig.4 ( a ) Simulateda n d ( b ) measureda b s o r p t i o n s p e c t r a o f t h e singlepeakM P A accordingt o the i nci de nta ngl e of E M w a v e f or TE po l a r i z a t i on ( c ) T he sa m e simulatedabsorptionspectraforTMpolarization 33 Fig.4.5(a)Dependenceoftheabsorptiononthegap(g2)ofproposeddual-bandMPA (b)Simulatedabsorptionspectraaccordingtothepolarizationangle(ϕ)ofEMwave.T h e insetistheschematicviewofvaryingpolarizationangleϕ.Inducedsurfacec u r r e n t s onthefrontandthebackmetalliclayersattwoabsorptionpeaksforϕ= (c) -45oa n d (d)45o.Redand blackarrowsaredesignated forthecurrentflowsont h e surfaceoffrontmetalliclayeratlowandhighabsorptionfr equencies,res pe cti ve ly 35 Fig.5.1(a)Structuralspecificationsoftheunitcell.(b)Zoomedimageof2 ×2u n i t cells forthefabricatedsample.(c)Arrangementfortheexperimentalsetup 38 Fig.5.2(a)SimulatedandexperimentalabsorptionspectraofthesuggestedMPA.D i s t r i b u t i o n s of (b)the inducedsurfacecurrentsonthetopandthebottomlayers,3- dimensional(c)magneticenergy,(d)electricenergyand(e)powerlossat250M H z .39 ...ThesisfortheDegreeofDoctorofPhilosophy Optimizationsforultra-smallandwide-incidentanglemetamaterialperfectabsorbersatlowfrequenc y by BuiXuanKhuyen SupervisedbyProfesso... Optimizationsforultra-smallandwide -incident- angle metamaterialperfectabsorbersat lowfrequency BuiXuanKhuyenD epartmentofPhysicsThe GraduateSchoolHanyan gUniversity Inrecentyears,theadvancesinmaterialsciencehavecontributedtothedevelopmento... 7.2 Metamaterialmodelandexperimentalsetup .53 II 7.3 Mechanismanalysisoftheperfectdual-absorptionpeakat30 5and 360.5MHz 54 7.4 Valuationofthedual-bandperfectabsorptionforwideincidentangle