Abstract: Underthevacuumandhighpowercondition,anunstableslightgapofconnectingstructureofacoaxialresonatorwillhaveseveralrisks,includingPIM(PassiveInterModulation)andEML(ElectroMagneticLeakage)problems.Thepercentageofgap′sintegralofsurfacecurrentinthewholeresonatorcavitywasanalyzed.Itshowsthatthegap′slocationisfartherawayfromhighsurfacecurrentstrengthpartofthecavity,thepercentageissmaller.Threekindsofcoaxialresonatorshavebeensimulated.Astableonewaspresentedforreducingthoserisks.Theconnectiongapofthecoaxialresonatorisfarawayfromelectricfieldwavenodesavailable.

Key words: highpower, coaxialresonator, electromagneticleak, passiveintermodulation