IFM Electronic ANT805, Operating Instructions Manual

Page: 11 / 17

UK
RFID UHF antennas
11
As evidence of the conformity with the basic requirements of this guideline there is
a number of harmonised standards that are published in the Official Journal of the
European Union�
The ifm antennas have a passive antenna structure� The system integrator is
responsible for meeting the standards - that means the person who combines
the individual components of an RFID system, in particular the readers and the
antennas� Therefore it is expressly recommended to acquire these standards�
Two important standards in connection with antennas are (not exhaustive)
EN 302208 and EN 50364: The first one deals with radio spectrum matters and
limits the maximally radiated power while
EN 50364 deals with the limitation of human exposure to electromagnetic fields�
As evidence of the antenna conformity with the standard EN 50364 the specific
absorption rate (SAR) is calculated numerically� The determined SAR values are
compared with the basic limit values of EN 50364 - classified to occupational
exposure, exposure of the general public and local exposure of head and
trunk and limbs� The WiRa is in general used for applications with a reading
area starting with 20 cm� At this distance the values are significantly below the
maximum SAR values permitted by law� In case that use is intended for smaller
distances, the respective SAR values are numerically calculated� The assumptions
taken as basis (such as operating mode of the RFID system and characteristics
of the human tissue) ensure a conservative estimate of the exposure (worst case
scenario)�
The calculation was also made for the most sensitive constellation
i�e� for the case that members of the general public stay permanently in direct
vicinity of the antenna with their head or trunk� If the distance between the person
and the antenna is less than 3 cm, the ANT820 ensures that the maximally allowed
SAR is not reached with an antenna input power of up to 0�34 W (25�31 dBm)� In
all other cases the ANT820 can be operated with the maximally radiated power
of 0�5 W ERP (27 dBm) or an antenna input power of 0�653 W (28�15 dBm)� The
table below shows the maximum input powers with which the antenna may be
supplied to ensure that the basic limit values of the SAR are not exceeded� Two
different types of exposure are differentiated:
Max� input power
ANT805 / ANT810 / ANT815 / ANT910
Direct contact with
ANT805 / ANT815
Direct contact with
ANT810 / ANT910
Occupational exposure
Limit values head and trunk 10 W/kg
Limit values local limbs 20 W/kg
Pin = 1 W
(30 dBm)
Pin = 0�5 W
(27 dBm)
General public
Local limbs exposure
Limit values local limps 4 W/kg
Pin = 1 W
(30 dBm)
Pin = 0�5 W
(27 dBm)
General public
Head and trunk exposure
Limit values head and trunk 2 W/kg
Pin = 1 W
(30 dBm)
Pin = 0�1 W
(20 dBm)