简介:TheTwin-LoopAntenna(TLA)hasbeenwidelyusedbecauseofitsbroadbandpropertyandsimplyfeeding,andsomemodifiedstructureshavebeendevel-opedfromitsprototypebyChineseengineers.ButtheexactdesigntheoryforTLAaccord-ingtotheimpedancecalculationhasnotyetbeenpublished.Inthispaper,theimpedanceofloopinaTLAisanalysedandcomputedbyusingthemethodofmoments,andthede-signformulaeandatwo-stepoptimizationprogramforextendingthebandwidthofinputimpedanceofTLAaredetailed.Anexampleofoptimizeddesignshowsthatthebandwidthcanbeincreasedupto36.4%forVSWR≤1.10,whichiswiderthanthebandwidthofra-diationpattern.