基站天線測(cè)量方法

國家通信導(dǎo)航設(shè)備質(zhì)檢中心基站天線測(cè)量方法TestspecificationofBasestationantennacenter1增益、半功率波束寬度、前后比及交叉極化比的測(cè)量可以采用遠(yuǎn)場(chǎng)或近場(chǎng)等測(cè)試方法，本標(biāo)準(zhǔn)敘述最常用的遠(yuǎn)場(chǎng)測(cè)試方法。Thetesthaslongdistanceandneardistanceforantennagain,beamwidthfronttobackratioamdpolarization.增益測(cè)量Gaintest2.1測(cè)量框圖見圖1testdraws:Theantenna被測(cè)天線SourceantennaTheantenna被測(cè)天線Sourceantenna源天線圖1天線增益測(cè)試框圖antennagaintestingdraws測(cè)量條件testqualification2.2.1被測(cè)天線具有相同的極化方式。Theantennaandsourceantennaissamepolarization2.2.2被測(cè)天線與源天線之間測(cè)量距離應(yīng)滿足：.(1)2(D2+d2).(1)L=X式中：L 源天線與被測(cè)天線距離m;thereisdistanceoftheantennatosourceantennaD 被測(cè)天線最尺寸m;thereismaxdimensionofsourceantennaD 源天線最大輻射尺寸m;thereismaxradiancyoftheantenna入一測(cè)試頻率波長(zhǎng)m。testfrequencybeamlong2.2.3被測(cè)天線應(yīng)安裝于場(chǎng)強(qiáng)基本均勻的區(qū)域內(nèi)，場(chǎng)強(qiáng)應(yīng)預(yù)先用一個(gè)半波偶極天線的有效天線體積內(nèi)進(jìn)行檢測(cè)，如果電場(chǎng)變化超過1.5dB，則認(rèn)為試驗(yàn)場(chǎng)是不可用的。此外，增益基準(zhǔn)天線在兩個(gè)正交極化面上測(cè)得的場(chǎng)強(qiáng)差值小于1dB。Theantennaundertestshouldbeplacedwithinaconstantfield,andthefieldstremgthcanfirstbemeasuredwithinthemagnetismfieldoftheantennaundertest.Shouldtheelectricfieldshowfluctuationsgreaterthan1.5dB,thetestfieldshouldgeconsideredunsuitable.Moreover,themeasuredfieldstremgrhsofthehorizontalamdverticalpolarizedcomponents,smeasuredbythestandardgainantenna,shouldmotdifferbymorethan1dB.2.2.4測(cè)量用信號(hào)發(fā)生器、接收機(jī)等測(cè)量設(shè)備和儀表應(yīng)具有良好的穩(wěn)定性、可靠性、動(dòng)態(tài)范圍和測(cè)量精度，以保證測(cè)量數(shù)據(jù)的正確性。測(cè)量用儀表應(yīng)有計(jì)量合格證，并在校驗(yàn)周期內(nèi)。Thesignalgenerator,receiverandotherequipmentandmetersusedfortestingshouldhavehighstability,reliability,measurementprecisionandwidedynamicrangeinordertoguaranteedataaccuracy.2.3測(cè)量步驟開始測(cè)量時(shí)，必須將被測(cè)天線和增益基準(zhǔn)天線交替做水平和俯仰調(diào)整，以確保每一天線在水平和俯仰上的最佳指向，使其接收的功率電平為最大。Whenbeginningameasurement,itisimportanttofirstperformazimuthandelevationadjustmentsonboththestandardgainantennaandtheantennaundertest,toensureeachdaythesameoptimumazimuthandelevatinareusedandmaximumpowerisattained.測(cè)量步驟如下：增益基準(zhǔn)天線與源天線對(duì)準(zhǔn)，通過轉(zhuǎn)接，使增益基準(zhǔn)天線與接收機(jī)相連接，此時(shí)接收機(jī)接收功率為P1(dBm);enchmarkantennaandsourceantennaatthesamelevelandtestingantennaconnectedwithreceiverthereceiveroiwerpowerisP1(dBm)被測(cè)天線與源天線對(duì)準(zhǔn)，通過轉(zhuǎn)接，使被測(cè)天線與接收機(jī)相連，步接收機(jī)接收功率為P2(dBm);testedantennaandsourceantennaatthesamelevelandtestingantennaconnectedwithreceiver,thereceiverpowerisP2(dBm)重復(fù)步驟A和B，(直至P1P2測(cè)量的重復(fù)性達(dá)至可以接受的程度);Repeatstep1andstep2被測(cè)天線某頻率點(diǎn)的增益G按式2計(jì)算:somefrequencygainoftestingantennacanbecalculatedasbelowformulaG=G0+(P2-P1)+N(dBm) (2)式中：G0—基準(zhǔn)天線的增益(dBi) G0—benchmarkantenna’sgainN一接收機(jī)輸入端分別到被測(cè)天線和增益基準(zhǔn)天線輸出端通路衰耗的修正dB;N—themodifieddBofaccesswastingthatreceiverinputtotestingantennaandbenchmarkantennaoutputrespectively在一個(gè)頻帶內(nèi)，至少測(cè)量高、中、低3個(gè)頻率點(diǎn)。Atsamefrequency,atleasttesthigh,middle,lowfrequency方向圖圓度、前后比、交叉極化比的測(cè)量，directiondrawing(fulldegreeantenna),beamwidth,fronttobackratio,actosspolarizationmeasurement.3.1測(cè)量示意圖見圖2。Testdrawsofdraw2測(cè)量條件滿足2.2Testsufficdofterm2.2圖2天線方向圓度、半功率波束寬度、前后比、交叉極化比測(cè)量示意圖Draw2:directiondegreedrawing,beamwidth,fronttobackratio,acrosspolarizationmeasurement.測(cè)量步驟testapproach3.3.1被測(cè)天線垂直安裝，并與源天線對(duì)準(zhǔn)。Theantennauprightnesssetpandaimatsourceantennapolarization3.3.2被測(cè)天線在測(cè)試轉(zhuǎn)臺(tái)作方位旋轉(zhuǎn)，并把接收到的電平作為角度的函數(shù)記錄下來，得天線水平面極化方向圖F(0),記錄天線水平半功率波束寬度％軸向最大接收電平？3，背向180°±30。范圍內(nèi)最大接收電平？4，全向最小接收電平P5；Theantennacircumgyrateonthetesttable,andnotethefunctionofdegreeplluseforreceiver,itisdrawsofpolarizationdegreedegreeathorizontalplaneF(0),andnotethebeamwidth0『receivermaxP3ofaxesdirection,receivermaxP4ofbackdirection180°±30°area.ReceiverminP5offulldirection.3.3.3保持被測(cè)天線于同極化最大接收電平位置，將源天線極化旋轉(zhuǎn)90°，并微調(diào)極化使被測(cè)天線在該位置接收電平最小；Keepmaxreceriverpluseofthepolarizationdegreeamtenna.Rotate90° thesourceantenna,theantennapluseminstayintheaddressofmustbealittletransform.3.3.4重復(fù)3.3.2的測(cè)試過程，得天線水平方向交叉極化方向圖f(0)，記錄軸向接收電平P6，背向180°±30°范圍內(nèi)最大接收電平P7;Repeat3.3.2testprocess,itisdrawsofpolarizationdegreeathorizontalplanef(0),receivermaxP6ofaxesdirection,receivermaxP7ofbackdirection180°±30°area.TOC\o"1-5"\h\z3.3.5測(cè)試結(jié)果：全向天線：方向圖圓度=土(P3-P5)/2 ⑶Testresultfulldirectionantenna:directiondegreedraw=土(P3-P5)/2單極化天線：水平面半功率波束寬度為0】Signalpolarizationantenna:horizontalbeamwidthis01.前后比=P3-P4 (4)Fronttobackratio:=P3-P4±45°雙極化天線：水平面半功率波束寬度為0]土45°degreeantenna:horizontalbeamwidthis01同極化前后比=P3-P4 (5)Samepolarizationfromnttobackratio=P3-P4交叉極化前后比=P3-P7 (6)Acrosspolarizationfronttobackratio=P3-P7天線前后比為同極化與交叉極化前后比中較差者Antennatronttobackratioisdifferenceofsamepolarizationandacrosspolarization軸向交叉極化比=P3-P6 (7)±30°(或土60°)范圍內(nèi)交叉極化比=Min[F(0)-f(0)] (8)±30°(or±60°)acrosspolarizationinnerarea=Min[F(0)-f(0)](注：目前±45°雙極化天線前后比僅測(cè)同極化前后比，交叉極化比僅測(cè)軸向極化比)(mark:now,testing±45°degreeantennafronttobackratioisonlysamepolarization,acrosspolarizationisonlytestaxesdirectionacrosspolarization)3.3.6被測(cè)天線水平安裝與源天線對(duì)準(zhǔn)，重復(fù)3.3.2測(cè)試過程，可以得天線垂直面半功率角02Theantennaaimatsourceantenofsetupinplane,repeat3.3.2testprocess,itisbeamdegree02ofantennaverticalplane.天線電下傾角測(cè)量testofantennadownobliquity測(cè)量條件滿足2.2。testqualificationsuffice2.24.2測(cè)量系統(tǒng)能保證收發(fā)天線等高，天線垂直安裝誤差小于0.2。時(shí)，天線可垂直架設(shè)，此時(shí)轉(zhuǎn)臺(tái)俯仰角為0°。反復(fù)調(diào)整轉(zhuǎn)臺(tái)俯仰使天線接收到的功率電平為最大，記錄這時(shí)轉(zhuǎn)臺(tái)的仰角為。，則天線電下傾角中=。。Testsystemmustbereceiveantennasamehigh,whenantennasetupuprightnesserrormustsmallthan0.2°,itiscanspanuprightness.Nowthetesttablepitchingisdegree0°,theantennareceivedfrepuencyplusemustbemaxofrepeatcompletetesttable,andnotepitchingdegree。attesttablenow,alsoantennadownobliquity①=。4.3測(cè)量系統(tǒng)不能保證收發(fā)天線等高，天線垂直安裝誤差大于0.2°時(shí)，天線建議天線采用水平架設(shè)，全向天線用一根，定向天線用一根，天線正反架設(shè)(繞測(cè)試系統(tǒng)水平軸旋轉(zhuǎn)180°)，測(cè)量示意圖見圖3。Testsystemnotpledgereceiveantennasamehigh,whenantennasetupuprightnesserrorbigthan0.2°,adviceusespanplaneofantenna.Fulldirectionuseonebase.Fixedantennauseonebasepositiveandnegativespan(planecircumvolve180°ofthetestsystem),testdrawfordraws3測(cè)量步驟testapproach4.4.1天線作360方位旋轉(zhuǎn)找出兩個(gè)主瓣出現(xiàn)的位置，計(jì)算兩主瓣之間的夾角分別為。3與。4(相對(duì)天線來說分別是上下角)；Antennacircumvolve360,findtwomainbeamappearplace,accounttwowiththemainbeamnipdegreeis。3and。4.(comparativelyofantennathisisupamddownnipdegree)4.4.2測(cè)量結(jié)果：天線電下傾角中=(180-04)/2=(03-180)/2o ..(9)Testresult:antennadownobliquityO=(180-04)/2=(。3-180)/2.圖3天線電下傾角測(cè)量示意圖downobliquitytestdraw駐波比測(cè)量stationarywavetest測(cè)量框圖見圖4Testdrawfordraw4測(cè)量條件 Testqualification被測(cè)天線應(yīng)該安裝在一個(gè)相對(duì)地沒有反射，并且離測(cè)試設(shè)備和測(cè)試人員相當(dāng)遠(yuǎn)的自由空間或無回波暗室。檢驗(yàn)測(cè)試場(chǎng)地合格的方法如下：Theantennamustsetupincomparativelynohaveecho,alsothetestequipmentandtestermuststayinfreedominterspaceornoechodarkroomfarofftheantenna.asfollowsmeansofthetestgroundiseligibility.當(dāng)被測(cè)天線（含其支撐結(jié)構(gòu)）在4個(gè)相隔45°水平方向上至少移動(dòng)半個(gè)波長(zhǎng)，向上、向下各移動(dòng)半個(gè)波長(zhǎng)時(shí)，如駐波比變化小于10%，則認(rèn)為測(cè)試場(chǎng)地是合格的。Whenthenantennamoveleastwisehalfbeamlonginbeapart45°of4pcs,whenmovehalfbeamlongofupanddown,ifatationarywavechangesmallthan10%soitisok.無回波暗箱無回波暗箱Nodarkroom圖4天線駐波比測(cè)量框圖ANTENNASTATIONARYWJVETESTDRAWS測(cè)量步驟TESTAPPROACH5.3.1將被測(cè)天線安裝在符合5.2測(cè)量條件的自由空間或模擬自由空間：Theantennasetupfor5.2testqualification’sfreedominterspaceorsimulatefreedominterspace按測(cè)量系統(tǒng)要求進(jìn)行系統(tǒng)核準(zhǔn)：itputupsystemadjustofthetestsystem5.3.3將測(cè)量系統(tǒng)與被測(cè)天線相連接，在工作頻率范圍內(nèi)進(jìn)行駐波比的測(cè)量，測(cè)試得的駐波讀數(shù)就是被測(cè)天線端口的電壓駐波比。theantennaconnectforthetestsystem,putupstationarywavetestintertheworkfrequencyarea.thisstationarywavereadingistheantennaporfspressurestationarywave.隔離度測(cè)量testisolationbetweenports測(cè)量框圖見圖5。Testdrawfordraw5測(cè)量條件滿足5.2。testqualificationsuffice5.2測(cè)量步驟testapproach6.3.1將被測(cè)天線安裝在符合5.2測(cè)量條件的自由空間或模擬自由空間TheAntennasetupfor5.2testqualificationisfreedominterspaceorsimulatefreedominterspace按測(cè)量系統(tǒng)要求進(jìn)行系統(tǒng)校準(zhǔn)：Itputupsystemadjustofthetestsystem6.3.3將射頻功率送到雙極化天線的一個(gè)端口，在另一端口的檢測(cè)接收功率，所測(cè)的功率電平值即為所測(cè)天線的隔離度。天線隔離度應(yīng)為工作頻帶內(nèi)各頻點(diǎn)隔離度中的最差值。Shallfrequencysendfordegreeantenna‘sanotherport,testreceivefrequencyatanotherport,sotestresultpluseisstationarywaveoftheantenna.Antennastationarywavemustbewiththefurthestdifferenceofeveryfrequencystationarywave。無回波室NODARKROOM圖5天線隔離度測(cè)量框圖antennastationarywavetestdraws交調(diào)測(cè)量compatibilitytesting7.1交調(diào)測(cè)量應(yīng)使用對(duì)應(yīng)頻段的“無源交調(diào)分析儀”進(jìn)行測(cè)試，分析儀置于測(cè)量“反射式交調(diào)”狀態(tài)，建議使用“掃頻”測(cè)試，測(cè)量框見圖6。雙極化天線測(cè)量天線測(cè)量時(shí)也可在另一端口接入一個(gè)低交調(diào)負(fù)載。Compatibilitytestingmustusecorresponding“compatibilityanalyseapparatus”fortesting,theanalysestayin“echocompatibility”，adviceuse"scan”test,thedrawisdraws6,whemthetestingatanotherportconnectofonelowcompatibilityloadfordegreeantenna.7.2測(cè)量條件testrequirement7.2.1滿足5.2。Implementasitem5.27.2.2無回波吸收體不能放在天線感應(yīng)近場(chǎng)內(nèi)，確保吸收體內(nèi)感應(yīng)回波不產(chǎn)生交調(diào)。同時(shí)還要保證吸收體之間相同極化間隙不產(chǎn)生泄漏。Inreflectedwaveabsorbedobjectcan’tlayneartoAntennaMagneticfieldinordertoitwon’tbringACmodulation.Atthesamepolaritybetweenofabsorbedobjectcan’tcomeforthmagneticleak;7.2.3確保連接天線電纜的剩余交調(diào)小于被測(cè)天線的交調(diào)。這可以通過在電纜一端接入一個(gè)低交調(diào)負(fù)載，在所需的形變