天线（无线技术cisco）

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1、思科无线产品天线订购指南September2008XiaogangWuxiawu@cisco.comQingXieqingxie@cisco.comPresentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential1版本信息§v1.02008/08/15§v1.12008/09/04Presentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential2思科无线产品天线

2、§FCCrequiresthatALLantennassoldbyaspreadspectrumvendorbecertifiedwiththeradiotheyaretobesoldwith§AllCiscoAironet-suppliedcables,RFdevicesandantennashavereverseTNC(RP-TNC)connectors§CiscoAironet-suppliedantennasmeetallFCCrules§Widevarietyantennasformostapplicatio

3、nsPresentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential3天线概念§DirectionalityOmni(360degreecoverage)directionalDirectional(limitedrangeofcoverage)§GainMeasuredindBianddBd.(0dBd=2.14dBi)Moregainmeansmorecoverage-incertaindirections§PolarizationAn

4、tennasareusedintheverticalpolarizationPresentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential4天线增益§Inlifeyouneverget“somethingfornothing;”thesameistrueinantennagain.§Ifthegainofanantennagoesup,thecoverageareaoranglegoesdown.§Coverageareasorradia

5、tionpatternsaremeasuredindegrees.§Theseanglesarereferredtoasbeamwidth,andhaveahorizontalandverticalmeasurement.Presentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential5天线理论–isotropic天线§Atheoreticalisotropicantennahasaperfect360degreeverticalSideV

6、iewandhorizontal(VerticalPattern)beamwidth.§ThisisareferenceforALLTopViewantennas(HorizontalPattern)Presentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential6天线理论-Dipole§Toobtainomni-directionalgainfromanisotropicantenna,theenergylobesare‘pushedin

7、’fromthetopandbottom,andforcedoutinadoughnuttypepattern.SideView§Thehigherthegain,(VerticalPattern)thesmallertheverticalbeamwidth,VerticalBeamwidthandthelargerthehorizontallobeareaNewPattern(withGain)§Thisisthetypicaldipolepattern.Gainofadipoleis2.14dBi(0dBd)Top

8、View(HorizontalPattern)Presentation_ID©2006CiscoSystems,Inc.Allrightsreserved.CiscoConfidential7高增益全向天线HighgainOmni-Directionals§Highgainomni-directionalantennaswillc