6.5.6.3
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]
0
-3
-6
-9
-12
-15
-18
Example
As can be seen in Directional radiation pattern in the ETSI frequency band (Page 276), the
maximum antenna gain in the horizontal plane is 6 dBi. In this plane and with the parallel
polarization axis at +70° or 300°, the antenna gain dropped to about 0 dBi. Therefore the dBr
value is 6. The antenna range is only 70° of the maximum range at + 50° or +300° from the Z
axis within the horizontal plane (see values shown in red in the directional radiation pattern:
Characteristic of the vertical plane of the antenna (Page 275) and the associated
representation of the reference system (Page 275)).
SIMATIC RF600
System Manual, 11/2018, J31069-D0171-U001-A21-7618
Read/write range [%]
100
70
50
35
25
18
13
Antennas
6.5 SIMATIC RF642A
279