电波暗室辐射场抗扰度场地均匀性校准规程

技术文件
3m法电波暗室辐射场抗扰度场地均匀性校准规程The method of uniform field strength calibration in 3m
chamber
第一版
The 1st edition
批准：日期：
审定：日期：
编制：日期：
2009.05.20 QJ/63.740-2009
1 适用范围和目的
Scope and object:
IEC61000-4-3测试中的场地均匀性校准
The calibration of field in IEC61000-4-3
2引用文件
Normative references
IEC 61000-4-3：1998
电磁兼容试验和测量技术射频电磁场辐射抗扰度试验
Testing and measurement techniques- Radiated, radio-frequency, electromagnetic field immunity test
3校准使用的仪器设备：
Test equipment:
①3m法电波暗室Anechoic chamber
②射频信号发生器RF signal generators:
③宽频功放power amplifier
④发射天线 field generating antennas
⑤场强探头 field strength monitoring antenna
⑥场强仪 field strength monitor
⑦功率仪 power meter
4 校准过程：
a) 场强探头位置的确定
Locate the field strength probe position
确认IEC61000-4-3标准测试中所使用垂直均匀域平面，定出需要校准的16个点的位置； Locate the vertical uniform area and the 16 measuring point for calibration as following:
Figure1
11
11 12
13
14
21 22 23 24
31 32 34 33 41 42 43 44
测试中，场强探头应放置在如图1所示的16个点上，其中场强探头的垂直投影应分别落在图2所示的地面上的1、2、3、4点上，如图2;场强探头的高度应在图3所示的1、2、3、4位置：
During the test, the field strength probe should be put in the 16 poison as shown in figure1,the vertical projection of the probe should located on position 1 to 4 on the ground as shown in figure 2, and the height of the probe should be at position 1 to 4 in figure 3.
Figure2
2 3
4 1
4
3
2
1 Figure 3
b)吸波材料位置的确认
Locate the absorber position
在地面上铺设使用的吸波材料，记录吸波材料的配设位置, mark1至mark4分别为吸波材料铺设的4个角；
Put additional absorber on the ground, and record the position of the 4 angle of the absorber as in figure 4:
Mark 3
Mark4 Mark 2
Mark 1
Figure 4
c)将天线放置在距离垂直均匀域平面3m远的位置处
Put the antenna on the point 3m away from uniform field area and make sure the direction of the antenna perpendicular to the uniform field area as in figure 5:
Uniform
field area
3m
Figure 5
d) 天线水平位置的定位
Locate the horizontal position of the antenna
分别记录天线水平极化的天线四角在暗室地面的上垂直投影点H1、H2、H3、H4及天线底座三脚所在位置1、2、3,同时记录天线四角距地面的高度h H 如图所示；
Record the horizontal position of the antenna as in figure 6, the vertical projection of the 4 angel of the antenna are marked as H1 to H4, and the position of the tripod are marked as 1 to 3. The heights of the 4 antenna angel are also recorded.
Figure 6
1
2
3
H1
H2
H3
H4
h H
e) 天线垂直位置的定位
Locate the vertical position of the antenna
分别记录天线垂直极化的天线四角在暗室地面的上垂直投影点H1、H2、H3、H4及天线底座三脚所在位置1、2、3,同时记录天线四角距地面的高度h v.如图所示；
Record the vertical position of the antenna as in figure 7, the vertical projection of the 4 angel of the antenna are marked as V1 to V4, and the position of the tripod are marked as 1 to 3. The heights of the 4 antenna angel are also recorded.
Figure7
f) 连接电缆的定位
Locate the connection cable
连接电缆，并记录电缆途径关键点，如下图；
Connect the signal cable to the antenna, and the point where the cable pass by should be record as in figure8:
3
1 2
V1
V2
V3
V4
H V
Figure 8
g)从80MHz开始，将场强探头放在某一均匀域测量点上（如22位置），给天线供以一定
前向功率信号Pc，使得在场强探头上测得的场强值约为所需计量的场强值Ec（如10V/m）Position the sensor at one of the 16 points in the grid ( for example 22), and set the frequency of the single generator output to the frequency 80MHz. Apply a forward power to the field-generating antenna so that the field strength obtained equals Ec(for example 10V/m).
Record the forward power and field strength readings.
h)以1%的前一频率为步长，重复步骤g），直到频率到达1GHz，生成的频率和输入前向
功率的表格如下：
Increase the frequency by 1% of the present frequency, and repeat step g) until the frequency reach 1GHz. The forward power and the field strength reading should be record in table 1.
Table 1
i)将探头分别移到移到网格中的其他15个位置，给天线供以上表1中的前向功率的信号
Pc，记录15个点上测量的每个频点上的实测场强，记录在下表中；
Move the sensor to other 15 positions in the grid. At each of position, the forward power in table1 should be used. And the measure field strength should be recorded in table 2
Table 2
5数据处理：
The calculating procedure:
a)将表2中的测量场强值按从低往高排列,如表3；
Sort the 1 field strength into ascending order as in table 3:
From low to high
table3
b)分别计算从小到大连续12个场强的最大场强差值R1至R5；
Calculate the field strength deviation R1 to R5 of continuous 12 point from low to high as following formula, and the data should be recorded in table 4:
R1=20log(e12/e1) R2=20 log(e13/e2) R3=20 log(e14/e3)
Table4
c)场强差值从R1向R5，第一个小于6dB的值对应的最小场强值(表4中)作为场地均匀性
校准的参考场强E T，并记录在下表中：
Check the field strength deviation R1 to R5, the first one less than 6dB should be marked and
Table 5
d) 利用下列公式得到测试场强E C 所对应的前向功率P c ；
Calculate the calibration forward powers as following formula, and record them in talbe6:
)
/log(20t c t c E E P P +=
Table 6。