Incloseproximitytothehumanbody,smallloopanten-
nasoutperformsmalldipoleandmonopoleantennas
[1].Theirsize,robustnessandlowmanufacturingcost
havemadesmallloopsthemostpopularantennafor
useinminiaturekeyfobtransmitters.Asmallloop
antennatypicallyconsistsofacircular,squareorrect-
angularcoppertraceonaprintedcircuitboard.Insome
cases,discretewiresareshapedintoloops.AN831MatchingSmallLoopAntennastorfPICDevicesEQUATION2:Author:JanvanNiekerk2MicrochipTechnologyInc.Ploss=IRlossINTRODUCTIONNotethatweassumethatthecurrentIisuniformaroundthesmallloop.ThisassumptionisonlyvalidifIncloseproximitytothehumanbody,smallloopanten-theloopcircumferenceissmallerthanonefifthofanasoutperformsmalldipolea
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