简介：Inrecentyears,agreatdealofefforthasbeenmadetoacreateterahertz(THz)waveabsorberbasedonmetamaterials(MM).Metamaterialsabsorbershaveavarietyofpotentialapplicationsincludingthermalemitters,detector,stealthtechnology,phaseimaging,etc.Inthispaper,wefirstlyintroducethebasicstructureandworkprincipleoftheTHzMMabsorbers,andatransmissionlinemodelisdevelopedfordevicesanalysis.ToexpandtheapplicationofTHzabsorbers,dual-bandandbroadbandTHzMMabsorbersaredesigned,fabricated,andmeasured.Attheendofthisarticle,thefuturedevelopmenttrendsofMMabsorbersarediscussed.

简介：Duetothegoodperformanceoftrackinglowelevationtargetascomparedtomicrowaveandthesuperiorityinpenetratingsmoke,dust,fog,anddrysnowascomparedtoinfrared,aKuandKadualbandexperimentalradarwasdesignedanddeveloped.ThisKuandKadualbandexperimentalradarisanarnplitute-comparisonmonopulsetrackingandguidingradar.Theconstitutionandparametersofthisradarisdescribedinparagraph2.Paragraph3dealswithtwoexperimentsfortestingthetrackingperformancesagainstlowelevationtarget,andgivestheimportantresults.BothKuandKabandhavehightrackingprecisionwhentheytrackhighelevationtargets,whileKabandhasmuchbettertrackingperformancethanKubandwhentheytracklowelevationtargets.Kabandcantrackahelicopter,whoseradarcrosssectionisabout6squaremeters,at40m,20m,10m,andeven5mabovesea.Kubandcanonlytrackthesamehelicopterat160mandhigherabovesea.

简介：Amethod,whichcanpredictthevalencebandoffsetsatstrainedlayerheterojunctionsunderdifferentstrainsituationsonlybycalculatingbandstructuresanddeformationparametersofthebulkmaterials,issuggested.Theapplicabilityofthismethodisverifiedbycalculationofthevalencebandoffsetsatstrainedlayerheterojuntions,suchasInP/InAs,InP/GaP,GaAs/InAs,GaP/GaAsandAlAs/InAswithvariousstrainconditions.

简介：AkindofDynamicFullBandwidthUtilized(DFBU)allocationalgorithmisintroduced.Thisalgorithmallowsasinglelinktousebandwidthfarbeyonditsfairsharebandwidthinamulti-servicepackettransportingsystem.Threeimportantparametersastheboundonmaximumandminimumbandwidth,themaximumpacketdelayandtheminimumbandwidthutilizationarediscussedandanalyzed.ResultsofexperimentsshowthattheDFBU-algorithmiscapableofmakingasinglelinkinthesystemtouseallthesparebandwidth(uptofull-bandwidth)whiletheperformanceoffairnessandQoSrequirementisstillguaranteed.

简介：Thisletterintroducesthedesignideas,simulationandtestresultsofanS-bandklystronwithbandwidthof11%,whichwasdevelopedbytheInstituteofElectronics,ChineseAcademyofSciences(IECAS).Onthepeakpowerlevelof800kW,theefficiencyofklystronismorethan30%;thegainismorethan41dB;theequal-drivingrelativeinstantaneousbandwidthisover11%;theaveragepowerislargerthan8kW,andthepowerfluctuationwithinbandwidthislessthan1.5dB.

简介：Anewultra-wide-band(UWB)hornantennabasedonthenonradiativedielectricwaveguide(NRD-guide)wasproposedtosolvetheproblemofUWBantennas,TEMhornsforexample,generallysufferfromlargesideleakage.Theruleofthetheoreticalselectionofitsparameters,ifNRD-guideisusedastheUWBantennas,isstudiedfirstly,thentheradiationcharacteristicsforanopen-endedNRD-guidearecalculatedbyFDTD(finite-differencetime-domain)method.

简介：Thewide-banddigitalreceivingsystemsrequiredigitaldownconversion(DDC)withhighdatarateandshorttuningtimeinordertointerceptthenarrow-bandsignalswithinbroadtuningbandwidth.ButtheserequirementscannotbemetbythecommercialDDC.Inthispaperanefficientimplementationarchitectureispresented.ItcombinestheflexibilityofDFTtuningwiththeefficiencyofthepolyphasefilterbankdecomposition.Byfirstdecimatingthedatapriortofilteringandmixing,thisarchitecturegivesabettersolutiontothemismatchbetweenthelowerhardwarespeedandhighdatarate.Thecomputersimulationsshowthefeasibilityofthisprocessingarchitecture.

简介：Thispaperpresentsacompacttriple-bandbandpassfilterbasedonmetamaterials.Theminiaturizationisrealizedbytheprincipleofphasecompensationofmetamaterial.Comparedwiththeconventionalhalf-wavelengthfilter,themetamaterialfilterhasasmallsizeof10mm×10mm.Thetriple-bandbandpassfilterperformancehasbeenvalidatedbytheelectromagneticsimulationsoftwareofhighfrequencystructuresimulator(HFSS).Theresultsillustratethatthefilterisdesignedwithcenterfrequenciesof2.4GHz,5.1GHzand8.8GHz,bandwidthsofabout7.9%(2.31—2.50GHz),7.8%(5.0—5.4GHz)and7.4%(8.50—9.15GHz),respectively,anditshowsgoodbandpasscharacteristics.

简介：Onthebasisoffree-electronicbands,theFermienergyiscalculatedbysummingthebandeigenvaluesoverBrillouin-xones,andtheresultsmayleadtounderstandthephysicalbasisoftheaverage-bond-energymodelinthecalculationofvalence-bandoffsets.

简介：Theaveragebondenergymethodispopularizedandappliedtostudybandoffsetsatstrainedlayerheterojunctions.BycarefulexaminationofhydrostaticanduniaxialstrainactionsonthebandoffsetparameterEmv,itisfoundthattheaveragebandoffsetparameterEmv,av=Em-Ev,avremainsbasicallyunchangedunderdifferentstrainconditions.Therefore,providedthebandoffsetparameterbeforestrainEmv,0ofbulkmaterialiscalculated,andtheexperimentvaluesofdeformationpotentialbandspin-orbit(SO)splittingenergy△0arequoted,theEmvatstrainedlayercanbeobtainedbyasimpleandconvenientalgebraiccalculation.Thusthevalencebandoffset△Evatstrainedlayerheterojunctincanalsobepredictedconveniently.Thissimplifiedcalcultationmethodischaracterizedbydecreasedcalculationamountandincreasedconvictionduetouseasmanyaspossibletheexperimentvalues.

简介：Asimpleandcompactmicrostrip-fedUltraWideBand(UWB)printedmonopoleantennawithband-notchedcharacteristicisproposedinthispaper.Theantennaiscomposedofasquareringwithasmallstripbar,sothattheantennaoccupiesabout7.69GHzbandwidthcovering3.11～10.8GHzwithexpectedbandrejectionfrom5.12GHzto5.87GHz.Aquasi-omnidirectionalandquasi-sym-metricalradiationpatternisalsoobtained.Thiskindofband-notchedUWBantennarequiresnoex-ternalfiltersandthusgreatlysimplifiesthesystemdesignofUWBwirelesscommunication.

简介：Inthispaperwedescribeafull-integratedcircuitcontainingallbuildingblocksofacompletedPLL-basedsynthesizerexceptforlowpassfilter(LPF).Thefrequencysynthesizerisdesignedforafrequencyhopping(FH)transceiveroperatingupto1.5GHzasalocaloscillator.ThearchitectureofVoltageControlledOscillator(VCO)isoptimizedtogetbetterperformance,andaphasenoiseof-111.85-dBc/Hz@1MHzandatuningrangeof250MHzaregainedatacentrefrequencyof1.35GHz.AnovelDual-ModulusPrescaler(DMP)isdesignedtoachieveaverylowjitterandalowerpower.ThesettlingtimeofPLLis80μswhilethereferencefrequencyis400KHz.ThismonolithicfrequencysynthesizeristointegrateallmainbuildingblocksofPLLexceptforthelowpassfilter,withamaximumVCOoutputfrequencyof1.5GHz,andisfabricatedwitha0.18μmmixedsignalCMOSprocess.Lowpowerdissipation,lowphasenoise,largetuningrangeandfastsettlingtimearegainedinthisdesign.

简介：以便快认识到与高分辨率调遣目标区域的成像活泼的卫星，匹配算法的新态度被开发。光线踪迹和印射的速度向量的一个严格的马赛克成像模型根据在成像目标和照相机之间的长带马赛克成像原则和关系被造焦点的飞机。三轴的态度基于调遣的路径的最佳的追踪的原则被推出。最后，几何可伸缩模拟整个推迟的时间和集成(TDI)充电被执行联合设备(电荷耦合器件)原型系统，卫星态度控制物理模拟站台和带的地球目标模拟器。试验性的结果证明算法能认识到匹配的乐队目标的无缝的拼接成像很好，证实算法的正确性。

简介：Anovelcompactelectromagneticbandgap(EBG)structureconstructedbyetchingtworeversesplitrings(RSRs)andinsertinginterleavingedge(IE)onthepatchofconventionalmushroom-likeEBG(CML-EBG)isinvestigated.SimulateddispersiondiagramsshowthattheproposedEBGstructurepresentsa13.6%sizereductioninthecenterfrequencyofthebandgap.TwocomparisonshavebeencarriedoutfortheanalysisoftheeffectoftheRSRsandIEconfiguration.Then,asampleofthisnovelEBGisfabricatedandtested,furtherexperimentaldataagreewellwiththesimulatedresults.Thus,thisEBGstructuremakesagoodcandidatetodecreasemutualcouplingincompactmicrostrippatcharray.

简介：录像显示器单位(VDU)的显示器图象能被收到并且分析意外电磁的噪音重建从一个个人计算机系统发出了。这个事实是在信息安全的信息漏威胁之一。因此，有效地并且快速形成PC显示以便为收到电磁的妥协辐射选择最好的频率范围，一个方法基于关联电源分析(CPA)和普通设备被建议。第一，当PC正在显示白黑色的垂直脱衣图象和黑图象时，到1GHz的10MHz的频率光谱分别地被测量大约10次。包含显示信息的频率范围能通过CPA被获得。然后，特殊图象信号在点频率和泛音附近被寻找。如果当显示全部的黑图象时，特殊信号消失，是真实特殊信号能被判定。最后，最好的收到频率范围能被全面考虑选CPA和信号的结果到特殊图象信号的噪音比率(SNR)。为了检查选择频率的有效性，变化，偷听实验被执行。结果证明选择频率范围能比另外的频率乐队检索高质量的图象。

简介：Wetheoreticallyproposethestructureofall-solidphotonicbandgapfibertosupportLP01modeat980nmandfourmodesofLP01,LP11,LP02andLP21atCbands.Weresearchcharacteristicsofthephotonicbandgabandapplypho-tonicfiberasgainmediumtofiberlasers,finallyrealizingseparateamplificationofLP11andLP21high-ordermodeswithsingle-modestablepumplightofLP01modeat980nm.Besides,werealizeLPllmodeandLP21modelaserout-putofdual-wavelength.

简介：为X乐队和8单位的一根真时间的延期线的系统分阶段执行数组天线被介绍。与piezotranslator(PZT)改变一个chirp栅栏的长度，可变延期被获得。计划被用于X乐队谁的分阶段执行的数组雷达寻找数据率是56/s。倾向的横梁被实时延期的错误影响，这被模仿。在beamforming模式和它的修改伏特之间的关系被讨论。

简介：ChaoticColpittscircuitswithfundamentalfrequencyf*beyond1GHzarestudiedbybothcircuitsimulationandexperimentusingPhilips'broadbandtransistorwiththresholdfrequencyof25GHz.ForthebasicconfigurationofColpittscircuitwithf*ofabout1.6GHz,broadbandcontinuouspowerspectracouldbeobtainedfrombothcircuitsimulationsandexperiments.TheharmonicsoftheobservedsignalfromAgilentPSA/ESAspectrumanalyzerareasnoticeableasfaras12GHz.AmodifiedColpittscircuitstructureemployingtheparasiticinductanceofBJT(BipolarJunctionTransistor)isalsoproposedandinvestigated.Bycircuitsimulation,chaoticattractorandbroadbandcontinuouspowerspectracouldbeobtainedfromthemodifiedColpittscircuitwithf*ofabout3.5GHz.Becausetheparasiticeffectsoftheprototypeboard,theexperimentresultofthemodifiedColpittscircuitdoesnotagreewellwiththesimulationresult.Thegapbetweenthesimulationandexperimentalresultcouldbebridgedbyreplacingthelumpedcircuitelementswithdistributedones.

简介：Inthispaper,thephotonicbandgapofphotoniccrystalswithchiralandnegative-indexmaterialsalternatelyisinvestigated.Itisshownthatthiskindofphotoniccrystalexhibitsverywidephotonicbandgap.Thephotoniccrystalswithadefectlayerhaveanarrowdefectmodeinthebandgap,whichcanbeusedasaverygoodfilteringmaterialbychoosingtheparametersofthedefectlayerproperly.

简介：TheISMbandat2.4GHzhasmostlybeenusedorplannedforindoorsystems.Thisbandisalsoattractiveforoutdoorsystemsowingtotheeaseofthesystemdeployment,asnofrequencylicensesarerequired.Inthispaper,amultiplesuccessiveinternalmultireflectionmodelisusedtoestimatethecomplexelectricpermittivityat2.4GHzband.Toobtainthedata,measurementsareperformedat160MHzbandwidthcenteredabout2.4GHzusingavectornetworkanalyzer,whichprovidesinformationabouttheamplitudeandphaseoftransmissioncoefficient.Severalsamplesofeachmaterialaremeasuredandtheresultsvaryfromsampletosample.Ithasalsobeenfoundthatsomeobstacleshavepolarizationbehaviour.