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2 RFID System Physical Anti-Collision Experimental Verification
Table 2.3 The recognition distance of tag group when the key tag position changes
Distance/m
1
2.413
3.149
3.436
3.070
2.362
2
2.382
3.063
3.394
3.085
2.458
3
2.416
3.121
3.442
3.094
2.423
4
2.396
3.081
3.435
3.131
2.396
5
2.427
3.039
3.383
3.063
2.486
Average
2.401
3.091
3.418
3.089
2.435
Fig. 2.6 Reading distance when the number of tag groups is unchanged and the structure is changed
represents the average value of the reading distance measurement of each placement
method.
Combined with the tag placement diagram and data results, it can be seen that
when the key tag is located in the center of the tag group, it has the least impact on
the performance of the tag group. When the key tag is located at the edge, it has
the greatest impact on the performance of tag group. At this point, the recognition
distance of tag group is the smallest, and the absolute value of tag group sensitivity
is the smallest. In addition, the maximum reading distance of tag group is less than
the reading distance of key tags, that is, the reading distance of tag group is less than
the reading distance of a single tag, and the sensitivity value of tag group is less than
the sensitivity value of a single tag.
Equation (2.4) is used to calculate the sensitivity of the tag group. Considering
that there is no obvious interference source in the laboratory environment, formula
(2.4) can be simplified as