Characteristics - Siemens Simatic RF600 System Manual

Radiated power
In order to comply with national directives with regard to the radiated power (which differ
depending on the location or country of use), the RF600 readers together with the antenna
cable(s) and antenna(s) must be exactly parameterized or configured.
This means that the product of the transmitted power P
G must always have the correct ratio with regard to the radiated power "EIRP" depending on
i
the location of use or the permissible frequency band.
Calculation of the radiated power is briefly described below.
Calculation of the radiated power
The radiated power is the total power radiated by the antenna in the room. The isotropic
radiator serves as the physical computing model which uniformly radiates the power into the
room (spherically, i.e. isotropic).
EIRP
Directional antennas combine the radiation, and therefore have a higher power density in the
main beam direction compared to an isotropic radiator. To enable antennas of different
design or Directional characteristic to be compared with one another, the equivalent isotropic
radiated power (EIRP) has been introduced which represents the effective power which must
be applied to an isotropic radiator in order to deliver the same power density in the main
beam direction of the antenna.
"EIRP" is the product of the transmitted power P
EIRP = P
ERP
Also common is specification of the equivalent radiated power referred to the half-wave
dipole "ERP" (effective radiated power):
Logarithmic and standardized data
Approximate calculations are easier to carry out as additions than as products, therefore the
logarithms are taken for the above equations and the power data standardized to 1 mW and
specified in decibels (dBm or dBi).
SIMATIC RF600
System Manual, xx/2014, J31069-D0171-U001-A15-7618
* G
0 i
RF600 system planning
4.3 Antenna configurations
of the reader and the antenna gain
0
and the antenna gain G
0
:
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