波导法兰 同轴接头.pptx

会计学Decibels&Nepers(分贝&奈培)PointofInterest:decibelsandNepersWhereR1andR2aretheloadresistanceandV1,V2arethevoltagesappearingacrosstheseloads.Iftheloadresistancesareequal,thenthisformulasimplifiesto:

Theratioofvoltagesacrossequalloadresistancecanalsobeexpressedintermsofnepers(Np,奈培)as:

Thecorrespondingexpressionintermsofpoweris

Sincevoltageisproportionaltothesquarerootofpower.Transmissionlineattenuationisoftenexpressedinnepers.Since1Npcorrespondstoapowerratioofe2,theconversionbetweennepersanddecibelsis:
Therearetwocommonlywaveguideflangesusedtoconnecttwowaveguidesections:

thecoverflange（接触式法兰）
thechokeflange（扼流式法兰）

Attention:
thetwowaveguidesectionsmusthavesamecrosssections.

侮茎掂湾琴蚜住屿楼储油扁绪联盲眠首禾视捍柯染椿庇起记脓两歪傅罐乖波导法兰&同轴接头波导法兰&同轴接头Thecoverflange(接触式法兰）Inhigh-powerapplicationsvoltagebreakdownmayoccuratthisjoint.Otherwise,thesimplicityofthecover-to-coverconnectionmakesitpreferableforgeneraluse.（高功率情况容易击穿）

TheSWRfromsuchajointistypicallylessthen1.03.Advantages
Simplefabrication
Lowcost

Disadvantages
Low-powerapplication
Easinessofbreakdown

Thechokeflange(扼流法兰)Anotherg/4lineisformedbyacircularaxialgrooveinthechokeflanges.Sotheshortcircuitattheright-handendofthisgrooveistransformedtoanopencircuitatthecontactpointoftheflanges.

Anyresistanceinthiscontactisinserieswithaninfinite(orveryhigh)impedanceandthushaslittleeffect.

Thenthishighimpedanceistransformedbacktoashortcircuit(orverylowimpedance)attheedgesofthewaveguides,toprovideaneffectivelow-resistancepathforcurrentflowacrossthejoint.
Sincethereisanegligiblevoltagedropacrosstheohmiccontactbetweentheflanges,voltagebreakdownisavoided.法兰连接处无物理接触，不容易被击穿.

Thus,thecover-to-chokeconnectioncanbeusefulforhigh-powerapplications.（可以在高功率情况下使用）

TheSWRforthisjointistypicallylessthan1.05,butismorefrequencydependentthanthecover-to-coverjoint.带宽较窄Advantages
High-powerapplication
Avoidablevoltagebreakdown

Disadvantages
Fabricationdifficulty
Sensitivefrequencydependency

PointofInterest:CoaxialConnectorsExplanationsRequirementsforc