Siemens SIMATIC RF615A, Руководство по эксплуатации, Страница: 24 / 34

Antenna patterns
6.4 Interpretation of directional radiation patterns
SIMATIC RF615A
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Operating Instructions, 09/2018, C79000-G8976-C511-01
6.4 Interpretation of directional radiation patterns
The following overview table will help you with the interpretation of directional radiation
patterns.
The table shows which dBi values correspond to which read/write ranges (in %): You can
read the radiated power depending on the reference angle from the directional radiation
patterns, and thus obtain information on the read/write range with this reference angle with
regard to a transponder.
The dBr values correspond to the difference between the maximum dBi value and a second
dBi value.
Deviation from maximum antenna gain [dBr] Read/write range [%]
0 100
-3 70
-6 50
-9 35
-12 25
-15 18
-18 13
Example
As can be seen from the Antenna pattern ETSI (Page 18), the maximum antenna gain is -
5 dBi. In the vertical plane, the antenna gain has dropped to approx. -11 dBi at +50°. This
means that the dBr value is -6. The antenna range is only 50% of the maximum range at
+ 50° from the Z axis within the vertical plane (see line shown in blue in the directional
radiation pattern: Characteristic of the vertical plane of the antenna and the associated
representation of the reference system).