Abstract: Therelationshipbetweentheaccumulationofmultipactingelectronsandthevariationofthetransmissionpropertiesinmicrowavecomponentswasstudied.  Anequivalentmediamodelwasproposedtodescribetheelectronaccumulationduringmultipactor,whereeffectsoftheelectrons′accumulationwereapproximatedasamediawithspecialrelativepermittivity.Thevalueofthespecialrelativepermittivitywascalculatedequivalentlycorrespondingtotheelectrondensity.Simulationandcalculationresultsindicatethatthetransmissionpropertiesofthemicrowavecomponentsremainunchangedwhenthedensityofelectronsincreasedfrom0/m³to1×10¹⁶/m³duringmultipactor.However,thereturnlossinthepassbandfrequenciesdropped15dBwhentheelectrondensityreached1×10¹⁷/m³.Astheincreasingoftheelectrondensity,thereflectionofelectromagneticwavecausedby“equivalent  media”increasedrapidlywhichmadethetransmissionpropertiesofthemicrowavecomponentsdeterioratessharply.Thesimulationwascoincidewiththeresultsoftheoreticalanalysis,whichindicatedthatthetransmissionwasevencutoffwhenthedensityofelectronsincreasedtothemagnitudeof4×10¹⁷/m³.Inaddition,whentheelectrondensityreached4×10¹⁷/m³(inthefrequencyrangeof2.5~5GHz),therelativepermittivityofthe“equivalentmedia”wasnegativeandthetransmissioncutoff.Thisresearchishelpfultounderstandthemechanismandtheelectricalcharacteristicschangesofmicrowavecomponentsduetomultipactor,providinganeffectivetheoreticalprincipleformultipactorsuppression.

Key words: multipactor, accumulationofelectrons, effectivedielectric, transmissionproperties, microwavecomponents