Influence Of Liquids And Non-Metallic Substances; Influence Of External Components - Siemens SIMATIC RF600 System Manual

Tags mounted directly onto metal
In general, tags must not be mounted directly onto metallic surfaces. Due to the nature of the
magnetic field, a minimum distance must be maintained between the tag antenna and
conductive materials. For further details on the special case of attaching transponders to
electrically conducting materials, see Section Auto-Hotspot and SectionAuto-Hotspot .
In the case of transponders that are not designed for mounting on metallic materials, the
minimum permissible distance from metal is 5 cm. The larger the distance between the
transponder and the metallic surface, the better the function of the transponder.
4.5.3

Influence of liquids and non-metallic substances

Non-metallic substances can also affect the propagation of electromagnetic waves.
When non-metallic substances or objects are located in the propagation field that can absorb
UHF radiation, these can alter the antenna field depending on their size and distance and
can even extinguish the field entirely.
The high-frequency damping effect of water and materials with a water content, ice and
carbon is high. Electromagnetic energy is partly reflected and absorbed.
Liquids and petroleum-based oils have low HF damping. Electromagnetic waves penetrate
the liquid and are only slightly weakened.
4.5.4

Influence of external components

The R&TTE guideline and the relevant standards govern the electromagnetic compatibility
requirements. This also concerns the external components of the RF600 system. Even
though the requirements for electromagnetic compatibility have been specified, various
components will still interfere with each other.
The performance of the RF600 system is highly dependent on the electromagnetic
environment of the antennas.
Reflections and interference
On the one hand, antenna fields will be weakened by absorbing materials and reflected by
conducting materials. When electromagnetic fields are reflected, the antenna field and
reflecting fields overlap (interference).
External components in the same frequency band
On the other hand, external components can transmit on the same frequency band as the
reader. Or the external components can transmit in different frequency bands with side
bands that overlap with the frequency band of the reader. This results in a reduction of the
"signal-to-noise" ratio which reduces the performance of an RF600 system.
If a DECT station that is transmitting in the 2 GHz band, for example, is located in the
receiving range of an antenna of the RF600 system, the performance of the write and read
accesses to the transponder will be affected.
SIMATIC RF600
System Manual, 05/2012, J31069-D0171-U001-A13-7618
4.5 The response of electromagnetic waves in the UHF band
RF600 system planning
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