User's Manual

RLX2 Industrial Hotspot Series
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Page180of208 ProSoftTechnology,Inc.
 February5,2015
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Anantennapatternwithequalornearlyequalintensityinalldirectionsis
omnidirectional.Intwodimensions,anomnidirectionalpatternappearsasacircle(in
threedimensions,anomnidirectionalantennapatternwouldbeasphere,butno
antennahastrueomnidirectionalpatterninthreedimensions).Anantennais
consideredomnidire
ctionalifoneofitstwodimensionalpatterns,eitherazimuthor
elevationpattern,isomnidirectional.
Beamwidthisanangularmeasurementofhowstronglythepowerisconcentratedina
particulardirection.Beamwidthisathreedimensiona lquantitybutcanbebrokeninto
two‐dimensionalslicesjustliketheantennapa
ttern.Thebeamwidthofan
omnidirectionalpatternis360degreesbecausethepowerisequalinalldirections.
AntennaGain
Antennagainisameasureofhowstronglyanantennaradiatesinitsdirectionof
maximumradiationintensitycomparedtohowstrongtheradiationwouldbeifthe
samepowerwereappliedtoanantennathatradiatedallofitspowerequallyinall
directions.Usingtheantennapattern,thegainisthedistan
cetothefurthestpointon
thepatternfromtheorigin.Foranomnidirectionalpattern,thegainis1,orequivalently
0dB.Thehighertheantennagainis,thenarrowerthebeamwidth,andviceversa.
Theamountofpowerreceivedbythereceivingantennaisproportionaltothe
transmitterpowermul
tipliedbythetransmitantennagain,multipliedbythereceiving
antennagain.Therefore,theantennagainsandtransmittingpowercanbetra dedoff. 
Forexample,doublingoneantenna gainhasthesameeffectasdoublingthe
transmittingpower.Doublingbothantennagainshasthesameeffectasquadru pling
thet
ransmittingpower.
AntennaPolarity
Antennapolarizationreferstothedir ectioninwhichtheelectromagneticfieldlines
pointasenergyradiatesawayfromtheantenna.Ingeneral,thepolarizationiselliptical.
Thesimplestandmostcommonformofthisellipticalpolarizationisastraightline,or
linearpolarization.Ofthetransmittedpowerthatreachesthereceivingan
tenna,only
theportionthathasthesamepolarizationasthereceivingantennapolarizationis
actuallyreceived.Forexample,ifthetransmitting antennapolarizationispointedinthe
verticaldirection(verticalpolarization,forshort),andthereceivingantennaalsohas
verticalpolarization,themaximumamountofpowerpossiblewillbereceived.Onthe
otherhan
d,ifthetransmitantennahasverticalpolarizationandthereceivingantenna
hashorizontalpolarization,nopowershouldbereceived.Ifthetwoantennashave