基站天线测量方法

Test specification of Base station antenna center

1 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 test

2.1测量框图见图1 test draws:

Source antenna

源天线

The antenna 被测天线 G ~ Singnal emit insulate 信号源发生器 隔离器

L Standard gain antenna 基准增益天线 转接 receiver 接收机

图1天线增益测试框图 antenna gain testing draws

2.2 测量条件 test qualification

2.2.1被测天线具有相同的极化方式。

The antenna and source antenna is same polarization 2.2.2被测天线与源天线之间测量距离应满足：

2(D2+d2)

……………………………….(1) L ≧ λ

式中：L──源天线与被测天线距离m; there is distance of the antenna to source antenna D──被测天线最尺寸m; there is max dimension of source antenna D──源天线最大辐射尺寸m; there is max radiancy of the antenna λ──测试频率波长m。 test frequency beam long

2.2.3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.

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 antenna connected 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 2 D. 被测天线某频率点的增益G按式2 计算:some frequency gain of testing antenna can be calculated as below formula

G=G0+(P2-P1)+N(dBm)………………………………………………...(2)

式中：G0－基准天线的增益(dBi) G0－benchmark antenna’s gain

N－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 respectively

E. 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 frequency

3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 2 3.2 测量条件满足2.2 Test sufficd of term 2.2 L

Φ

源天线 天线下倾角 被测天线 Antenna down obliquity Source antenna The antenna

测试转台test change table

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 approach

3.3.1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 polarization

3.3.2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θ1

Signal 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 ,across polarization 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θ2 The 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 obliquity

4.1测量条件满足2.2。 test qualification suffice 2.2

4.2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θ，则天线电下倾角Φ=θ。

Test system must be receive antenna same high, when antenna set up uprightness error must small than 0.2°, it is can span uprightness. Now the test table pitching is degree 0°, the antenna received frepuency pluse must be max of repeat complete test table , and note pitching degreeθ at test table now, also antenna down obliquity Φ=θ

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。

Test system not pledge receive antenna same high, when antenna set up uprightness error big than

0.2°, advice use span plane of antenna. Full direction use one base. Fixed antenna use one base positive and negative span (plane circumvolve 180° of the test system), test draw for draws 3 4.4测量步骤 test approach

4.4.1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θ3与θ4

(相对天线来说分别是上下角)﹔

Antenna circumvolve 360, find two main beam appear place, account two with the main beam nip degree isθ3 andθ4. (comparatively of antenna this is up amd down nip degree) 4.4.2测量结果：天线电下倾角Φ = (180-θ4)/2 = (θ3-180)/2。………………..(9) Test result: antennadown obliquityΦ = (180-θ4)/2 = (θ3-180)/2 .

L

被测天线 The antenna 源天线 Source antenna 测试转台test change table 图3天线电下倾角测量示意图 down obliquity test draw

5驻波比测量 stationary wave test

5.1测量框图见图 4 Test draw for draw 4 5.2测量条件 Test qualification

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:

The antenna must set up in comparatively no have echo, also the test equipment and tester must stay in freedom interspace or no echo darkroom far off the antenna . as follows means of the test ground is

eligibility.

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。

When then antenna move leastwise half beam long in be apart 45°of 4 pcs, when move half beam long of up and down, if atationary wave change small than 10% so it is ok .

测量系统 Test system 无回波暗箱 No darkroom

图4 天线驻波比测量框图 ANTENNA STATIONARY WAVE TEST DRAWS

5.3测量步骤 TEST APPROACH

5.3.1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：

The antenna set up for 5.2 test qualification’s freedom interspace or simulate freedom interspace 5.3.2按测量系统要求进行系统核准：it put up system adjust of the test system

5.3.3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。

the antenna connect for the test system, put up stationary wave test inter the work frequency area. this stationary wave reading is the antenna port’s pressure stationary wave. 6.隔离度测量 test isolation between ports 6.1测量框图见图5。Test draw for draw 5 6.2测量条件满足5.2。test qualification suffice 5.2 6.3测量步骤test approach

6.3.1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

The Antenna set up for 5.2 test qualification is freedom interspace or simulate freedom inter space 6.3.2按测量系统要求进行系统校准：It put up system adjust of the test system

6.3.3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。

Shall frequency send for degree antenna ‘s another port, test receive frequency at another port, so test result pluse is stationary wave of the antenna. Antenna stationary wave must be with the furthest difference of every frequency stationary wave。

Network analyse apparatus 网络分析仪

无回波室 NO DARKROOM

图5 天线隔离度测量框图 antenna stationary wave test draws

7.交调测量 compatibility testing

7.1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。

Compatibility testing must use corresponding “compatibility analyse apparatus” for testing, the analyse stay in “echo compatibility”, advice use “scan” test , the draw is draws6,whem the testing at another port connect of one low compatibility load for degree antenna.

被测天线 THE ANTENNA

Compatibility analyse apparatus 无源交调分析仪 O1port 2port O 图6 天线交调测量框图

7.2测量条件 test requirement

7.2.1满足5.2。Implement as item 5.2

7.2.2 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。

Inreflected wave absorbed object can’t lay near to Antenna Magnetic field in order to it won’t bring AC modulation. At the same polarity between of absorbed object can’t come forth magnetic leak; 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，在所需的形变范围内移动电缆而测得。

In order to guarantee the surplus AC modulation of the cable connected to the Antenna less than that ‘s of measures AC amplitude, it can import the low AC modulation subcarrier to control the portable cable to change the scope of requirement.

7.2.4降低连接电缆损耗。当电缆损耗超过1dB，无源交调测量误差显着增大。

Play down the connected cable consumption. No power AC modulation can produce evidently and biggish error when the cable comsumption more than 1DB. 7.3测量步骤 The step of Measure

7.3.1将被测天线与系统相连接，并保证接触可靠：

PLS connected the Antenna to the Measures system firm and reliably.

7.3.2在工作频带内选择合适的两频率f1,f2,使交调产物f3=2fl-f2(或2f2-f1)落在工作频带内：

Select two proper frequency, one is f1,other f2 consist in scope of working frequency, it can make the f3 frequency(f3=2f1-f2 or 2f2-f1) consist in the working frequency. 7.3.3调整输出功率，使输送到被测天线上的功率各为20W：

Adust the output power and let the f1,f2 power that output to the measured Antenna reach 20w respectively.

7.3.4利用无源交调分析仪可直接读出交调电平。

It can read the data by the apparatus passive AC modulation.