国家通信导航设备质检中心──基站天线测量方法Test specification of Base station antenna center1 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。
The test has long distance and near distance for antenna gain,beam width front to back ratio amd polarization.2 增益测量 Gain test2.1测量框图见图1 test draws:图1天线增益测试框图 antenna gain testing draws2.2 测量条件 test qualification2.2.1被测天线具有相同的极化方式。
The antenna and source antenna is same polarization2.2.2被测天线与源天线之间测量距离应满足：式中：L ──源天线与被测天线距离m; there is distance of the antenna to source antennaD ──被测天线最尺寸m; there is max dimension of source antennaD ──源天线最大辐射尺寸m; there is max radiancy of the antennaλ──测试频率波长m 。
test frequency beam long2.2.3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 。
The antenna under test should be placed within a constant field,and the field stremgth can first be measured within the magnetism field of the antenna under test. Should the electric field show fluctuations greater than 1.5dB, the test field should ge considered unsuitable. Moreover, the measured field stremgrhs of the horizontal amd vertical polarized components, s measured by the standard gain antenna, should mot differ by more than 1dB.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。
The signal generator,receiver and other equipment and meters used for testing should have high stability, reliability,measurement precision and wide dynamic range in order to guarantee data accuracy.Source antenna源天线 The antenna 隔离器 信号源发生器 L ≧ 2(D 2+d 2) λ (1)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。
When beginning a measurement, it is importantto first perform azimuth and elevation adjustments on both thestandard gain antenna and the antenna under test, to ensure each day the same optimum azimuth and elevatin are used and maximum power is attained.测量步骤如下：A.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)﹔enchmark antenna and source antenna at the same level and testing antennaconnected with receiver the receiver oiwer power is P1(dBm)B.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);tested antenna and source antenna at the same level and testing antenna connected with receiver,the receiver power is P2(dBm)C.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)﹔Repeat step 1 and step 2D.被测天线某频率点的增益G按式2 计算:some frequency gain of testing antenna can becalculated as below formulaG=G0+(P2-P1)+N(dBm) (2)式中：G0－基准天线的增益(dBi) G0－benchmark antenna’s gainN－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－the modified dB of access wasting that receiver input to testing antenna and benchmark antenna output respectivelyE.在一个频带内，至少测量高、中、低3个频率点。
At same frequency, at least test high, middle, low frequency3方向图圆度、前后比、交叉极化比的测量，direction drawing(full degree antenna), beam width, front to back ratio,actoss polarization measurement.3.1 测量示意图见图2。
Test draws of draw 23.2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: direction degree drawing, beam width, front to back ratio,across polarization measurement.3.3测量步骤test approach3.3.1被测天线垂直安装，并与源天线对准。
The antenna uprightness set p and aim at source antenna polarization3.3.2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(θ)，记录天线水平半功率波束宽度θ1轴向最大接收电平P3，背向180°±30°范围内最大接收电平P4，全向最小接收电平P5﹔The antenna circumgyrate on the test table, and note the function of degree plluse for receiver, it is draws of polarization degree degree at horizontal plane F(θ), and note the beam widthθ1,receiver max P3 of axes direction, receiver max P4 of back direction 180°±30°area. Receiver min P5 of full direction.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﹔Keep max receriver pluse of the polarization degree amtenna. Rotate 90°the source antenna, the antenna pluse min stay in the address of must be a little transform.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 (θ)，记录轴向接收电平P6，背向180°±30°范围内最大接收电平P7﹔Repeat 3.3.2 test process, it is draws of polarization degree at horizontal plane f(θ), receiver max P6 of axes direction, receiver max P7 of back direction 180°±30°area.3.3.5测试结果：全向天线：方向图圆度= ±( P3-P5) / 2 (3)Test result full direction antenna : direction degree draw = ±( P3-P5 ) / 2单极化天线：水平面半功率波束宽度为θ1Signal polarization antenna: horizontal beam width isθ1.前后比= P3-P4 (4)Front to back ratio: =P3-P4±45°双极化天线：水平面半功率波束宽度为θ1±45°degree antenna : horizontal beam width isθ1同极化前后比=P3-P4 (5)Same polarization fromnt to back ratio = P3-P4交叉极化前后比= P3-P7 (6)Across polarization front to back ratio = P3-P7天线前后比为同极化与交叉极化前后比中较差者Antenna tront to back ratio is difference of same polarization and across polarization轴向交叉极化比＝P3-P6 (7)±30°(或±60°)范围内交叉极化比= Min[F(θ)-f(θ)] (8)±30°(or±60°) across polarization inner area =Min [F(θ)-f(θ)](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°degree antenna front to back ratio is only same polarization ,acrosspolarization is only test axes direction across polarization )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θ2The antenna aim at source anten of set up in plane, repeat 3.3.2 test process, it is beam degree θ2 ofantenna vertical plane.4天线电下倾角测量test of antenna down obliquity4.1测量条件满足2.2。