Interpretation Of Directional Radiation Patterns - Siemens SIMATIC RF600 Series System Manual

Overview of the antenna parameters
Table 5- 8
Azimuth section
Elevation section
Typical antenna gain
in the frequency band 902 to 928 MHz
Antenna axis ratio
You will find more information on the antennas in the section "Guidelines for selecting RFID
UHF antennas (Page 51)".
5.2.2.2

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.
Table 5- 9
Deviation from maximum antenna gain [dBr]
0
-3
-6
-9
-12
-15
-18
Example
As can be seen in the section Antenna diagram RF615R (ETSI) (Page 105), the maximum
antenna gain 0 dB is standardized. In the Azimuth diagram, the antenna gain falls by 3°dB at
approximately ± 39°. This means that the dBr value is -3. The antenna range is only 50 % of
the maximum range at ± 39° from the Z axis within the horizontal plane.
SIMATIC RF600
System Manual, 11/2018, J31069-D0171-U001-A21-7618
Maximum linear electrical aperture angle at 915 MHz:
Range of antenna depending on antenna gain
Polarization (circular)
100°
100°
0 dBi
2 dB
Read/write range [%]
100
70
50
35
25
18
13
Readers
5.2 SIMATIC RF615R
109