基站天线测量方法

国家通信导航设备质检中心基站天线测量方法TestspecificationofBasestationantennacenter1增益、半功率波束宽度、前后比及交叉极化比的测量可以采用远场或近场等测试方法，本标准叙述最常用的远场测试方法。Thetesthaslongdistanceandneardistanceforantennagain,beamwidthfronttobackratioamdpolarization.增益测量Gaintest2.1测量框图见图1testdraws:Theantenna被测天线SourceantennaTheantenna被测天线Sourceantenna源天线图1天线增益测试框图antennagaintestingdraws测量条件testqualification2.2.1被测天线具有相同的极化方式。Theantennaandsourceantennaissamepolarization2.2.2被测天线与源天线之间测量距离应满足：.(1)2(D2+d2).(1)L=X式中：L 源天线与被测天线距离m;thereisdistanceoftheantennatosourceantennaD 被测天线最尺寸m;thereismaxdimensionofsourceantennaD 源天线最大辐射尺寸m;thereismaxradiancyoftheantenna入一测试频率波长m。testfrequencybeamlong2.2.3被测天线应安装于场强基本均匀的区域内，场强应预先用一个半波偶极天线的有效天线体积内进行检测，如果电场变化超过1.5dB，则认为试验场是不可用的。此外，增益基准天线在两个正交极化面上测得的场强差值小于1dB。Theantennaundertestshouldbeplacedwithinaconstantfield,andthefieldstremgthcanfirstbemeasuredwithinthemagnetismfieldoftheantennaundertest.Shouldtheelectricfieldshowfluctuationsgreaterthan1.5dB,thetestfieldshouldgeconsideredunsuitable.Moreover,themeasuredfieldstremgrhsofthehorizontalamdverticalpolarizedcomponents,smeasuredbythestandardgainantenna,shouldmotdifferbymorethan1dB.2.2.4测量用信号发生器、接收机等测量设备和仪表应具有良好的稳定性、可靠性、动态范围和测量精度，以保证测量数据的正确性。测量用仪表应有计量合格证，并在校验周期内。Thesignalgenerator,receiverandotherequipmentandmetersusedfortestingshouldhavehighstability,reliability,measurementprecisionandwidedynamicrangeinordertoguaranteedataaccuracy.2.3测量步骤开始测量时，必须将被测天线和增益基准天线交替做水平和俯仰调整，以确保每一天线在水平和俯仰上的最佳指向，使其接收的功率电平为最大。Whenbeginningameasurement,itisimportanttofirstperformazimuthandelevationadjustmentsonboththestandardgainantennaandtheantennaundertest,toensureeachdaythesameoptimumazimuthandelevatinareusedandmaximumpowerisattained.测量步骤如下：增益基准天线与源天线对准，通过转接，使增益基准天线与接收机相连接，此时接收机接收功率为P1(dBm);enchmarkantennaandsourceantennaatthesamelevelandtestingantennaconnectedwithreceiverthereceiveroiwerpowerisP1(dBm)被测天线与源天线对准，通过转接，使被测天线与接收机相连，步接收机接收功率为P2(dBm);testedantennaandsourceantennaatthesamelevelandtestingantennaconnectedwithreceiver,thereceiverpowerisP2(dBm)重复步骤A和B，(直至P1P2测量的重复性达至可以接受的程度);Repeatstep1andstep2被测天线某频率点的增益G按式2计算:somefrequencygainoftestingantennacanbecalculatedasbelowformulaG=G0+(P2-P1)+N(dBm) (2)式中：G0—基准天线的增益(dBi) G0—benchmarkantenna’sgainN一接收机输入端分别到被测天线和增益基准天线输出端通路衰耗的修正dB;N—themodifieddBofaccesswastingthatreceiverinputtotestingantennaandbenchmarkantennaoutputrespectively在一个频带内，至少测量高、中、低3个频率点。Atsamefrequency,atleasttesthigh,middle,lowfrequency方向图圆度、前后比、交叉极化比的测量，directiondrawing(fulldegreeantenna),beamwidth,fronttobackratio,actosspolarizationmeasurement.3.1测量示意图见图2。Testdrawsofdraw2测量条件满足2.2Testsufficdofterm2.2图2天线方向圆度、半功率波束宽度、前后比、交叉极化比测量示意图Draw2:directiondegreedrawing,beamwidth,fronttobackratio,acrosspolarizationmeasurement.测量步骤testapproach3.3.1被测天线垂直安装，并与源天线对准。Theantennauprightnesssetpandaimatsourceantennapolarization3.3.2被测天线在测试转台作方位旋转，并把接收到的电平作为角度的函数记录下来，得天线水平面极化方向图F(0),记录天线水平半功率波束宽度％轴向最大接收电平？3，背向180°±30。范围内最大接收电平？4，全向最小接收电平P5；Theantennacircumgyrateonthetesttable,andnotethefunctionofdegreeplluseforreceiver,itisdrawsofpolarizationdegreedegreeathorizontalplaneF(0),andnotethebeamwidth0『receivermaxP3ofaxesdirection,receivermaxP4ofbackdirection180°±30°area.ReceiverminP5offulldirection.3.3.3保持被测天线于同极化最大接收电平位置，将源天线极化旋转90°，并微调极化使被测天线在该位置接收电平最小；Keepmaxreceriverpluseofthepolarizationdegreeamtenna.Rotate90° thesourceantenna,theantennapluseminstayintheaddressofmustbealittletransform.3.3.4重复3.3.2的测试过程，得天线水平方向交叉极化方向图f(0)，记录轴向接收电平P6，背向180°±30°范围内最大接收电平P7;Repeat3.3.2testprocess,itisdrawsofpolarizationdegreeathorizontalplanef(0),receivermaxP6ofaxesdirection,receivermaxP7ofbackdirection180°±30°area.TOC\o"1-5"\h\z3.3.5测试结果：全向天线：方向图圆度=土(P3-P5)/2 ⑶Testresultfulldirectionantenna:directiondegreedraw=土(P3-P5)/2单极化天线：水平面半功率波束宽度为0】Signalpolarizationantenna:horizontalbeamwidthis01.前后比=P3-P4 (4)Fronttobackratio:=P3-P4±45°双极化天线：水平面半功率波束宽度为0]土45°degreeantenna:horizontalbeamwidthis01同极化前后比=P3-P4 (5)Samepolarizationfromnttobackratio=P3-P4交叉极化前后比=P3-P7 (6)Acrosspolarizationfronttobackratio=P3-P7天线前后比为同极化与交叉极化前后比中较差者Antennatronttobackratioisdifferenceofsamepolarizationandacrosspolarization轴向交叉极化比=P3-P6 (7)±30°(或土60°)范围内交叉极化比=Min[F(0)-f(0)] (8)±30°(or±60°)acrosspolarizationinnerarea=Min[F(0)-f(0)](注：目前±45°双极化天线前后比仅测同极化前后比，交叉极化比仅测轴向极化比)(mark:now,testing±45°degreeantennafronttobackratioisonlysamepolarization,acrosspolarizationisonlytestaxesdirectionacrosspolarization)3.3.6被测天线水平安装与源天线对准，重复3.3.2测试过程，可以得天线垂直面半功率角02Theantennaaimatsourceantenofsetupinplane,repeat3.3.2testprocess,itisbeamdegree02ofantennaverticalplane.天线电下倾角测量testofantennadownobliquity测量条件满足2.2。testqualificationsuffice2.24.2测量系统能保证收发天线等高，天线垂直安装误差小于0.2。时，天线可垂直架设，此时转台俯仰角为0°。反复调整转台俯仰使天线接收到的功率电平为最大，记录这时转台的仰角为。，则天线电下倾角中=。。Testsystemmustbereceiveantennasamehigh,whenantennasetupuprightnesserrormustsmallthan0.2°,itiscanspanuprightness.Nowthetesttablepitchingisdegree0°,theantennareceivedfrepuencyplusemustbemaxofrepeatcompletetesttable,andnotepitchingdegree。attesttablenow,alsoantennadownobliquity①=。4.3测量系统不能保证收发天线等高，天线垂直安装误差大于0.2°时，天线建议天线采用水平架设，全向天线用一根，定向天线用一根，天线正反架设(绕测试系统水平轴旋转180°)，测量示意图见图3。Testsystemnotpledgereceiveantennasamehigh,whenantennasetupuprightnesserrorbigthan0.2°,adviceusespanplaneofantenna.Fulldirectionuseonebase.Fixedantennauseonebasepositiveandnegativespan(planecircumvolve180°ofthetestsystem),testdrawfordraws3测量步骤testapproach4.4.1天线作360方位旋转找出两个主瓣出现的位置，计算两主瓣之间的夹角分别为。3与。4(相对天线来说分别是上下角)；Antennacircumvolve360,findtwomainbeamappearplace,accounttwowiththemainbeamnipdegreeis。3and。4.(comparativelyofantennathisisupamddownnipdegree)4.4.2测量结果：天线电下倾角中=(180-04)/2=(03-180)/2o ..(9)Testresult:antennadownobliquityO=(180-04)/2=(。3-180)/2.图3天线电下倾角测量示意图downobliquitytestdraw驻波比测量stationarywavetest测量框图见图4Testdrawfordraw4测量条件 Testqualification被测天线应该安装在一个相对地没有反射，并且离测试设备和测试人员相当远的自由空间或无回波暗室。检验测试场地合格的方法如下：Theantennamustsetupincomparativelynohaveecho,alsothetestequipmentandtestermuststayinfreedominterspaceornoechodarkroomfarofftheantenna.asfollowsmeansofthetestgroundiseligibility.当被测天线（含其支撑结构）在4个相隔45°水平方向上至少移动半个波长，向上、向下各移动半个波长时，如驻波比变化小于10%，则认为测试场地是合格的。Whenthenantennamoveleastwisehalfbeamlonginbeapart45°of4pcs,whenmovehalfbeamlongofupanddown,ifatationarywavechangesmallthan10%soitisok.无回波暗箱无回波暗箱Nodarkroom图4天线驻波比测量框图ANTENNASTATIONARYWJVETESTDRAWS测量步骤TESTAPPROACH5.3.1将被测天线安装在符合5.2测量条件的自由空间或模拟自由空间：Theantennasetupfor5.2testqualification’sfreedominterspaceorsimulatefreedominterspace按测量系统要求进行系统核准：itputupsystemadjustofthetestsystem5.3.3将测量系统与被测天线相连接，在工作频率范围内进行驻波比的测量，测试得的驻波读数就是被测天线端口的电压驻波比。theantennaconnectforthetestsystem,putupstationarywavetestintertheworkfrequencyarea.thisstationarywavereadingistheantennaporfspressurestationarywave.隔离度测量testisolationbetweenports测量框图见图5。Testdrawfordraw5测量条件满足5.2。testqualificationsuffice5.2测量步骤testapproach6.3.1将被测天线安装在符合5.2测量条件的自由空间或模拟自由空间TheAntennasetupfor5.2testqualificationisfreedominterspaceorsimulatefreedominterspace按测量系统要求进行系统校准：Itputupsystemadjustofthetestsystem6.3.3将射频功率送到双极化天线的一个端口，在另一端口的检测接收功率，所测的功率电平值即为所测天线的隔离度。天线隔离度应为工作频带内各频点隔离度中的最差值。Shallfrequencysendfordegreeantenna‘sanotherport,testreceivefrequencyatanotherport,sotestresultpluseisstationarywaveoftheantenna.Antennastationarywavemustbewiththefurthestdifferenceofeveryfrequencystationarywave。无回波室NODARKROOM图5天线隔离度测量框图antennastationarywavetestdraws交调测量compatibilitytesting7.1交调测量应使用对应频段的“无源交调分析仪”进行测试，分析仪置于测量“反射式交调”状态，建议使用“扫频”测试，测量框见图6。双极化天线测量天线测量时也可在另一端口接入一个低交调负载。Compatibilitytestingmustusecorresponding“compatibilityanalyseapparatus”fortesting,theanalysestayin“echocompatibility”，adviceuse"scan”test,thedrawisdraws6,whemthetestingatanotherportconnectofonelowcompatibilityloadfordegreeantenna.7.2测量条件testrequirement7.2.1满足5.2。Implementasitem5.27.2.2无回波吸收体不能放在天线感应近场内，确保吸收体内感应回波不产生交调。同时还要保证吸收体之间相同极化间隙不产生泄漏。Inreflectedwaveabsorbedobjectcan’tlayneartoAntennaMagneticfieldinordertoitwon’tbringACmodulation.Atthesamepolaritybetweenofabsorbedobjectcan’tcomeforthmagneticleak;7.2.3确保连接天线电缆的剩余交调小于被测天线的交调。这可以通过在电缆一端接入一个低交调负载，在所需的形变