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EMC and the Radiation of Electromagnetic Waves
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To protect humans and nature from electromagnetic hazards, the health
and safety legislation for the deployment of (cellular) base
stations (e.g. WiMAX, UMTS, GSM,
IS-95, IS-136, cdma one,....)
becomes more
and more restrictive. This is driven by the goal to reduce health risks
especially for young children and for persons working/living close to
radiating antennas.
Different public authorities issued recommendations based
on guidelines formulated by the International Committee on Non Ionising
Radio Protection (ICNIRP). Today, these recommendations must be
fulfilled for
each new transmitting antenna.
The recommendations define limits to protect the public and
those working close to transmitting antennas from electromagnetic field
hazards. Therefore an assessment of the radiated electric and magnetic
field strength for different frequency ranges must be carried out
before installing a base station or transmitter.
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Display of exposure
due to two GSM 900
transmitters in a dense city center
(with
respect
to the
national thresholds of Germany)
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The EMC module of WinProp
The
figure
shows the superposition of the electric field
radiated from two
GSM 900 antennas mounted at the wall of a building in
a dense urban scenario.
ProMan
can accurately predict the
radiated electric and magnetic fields
of antennas. So the tool prevents mobile network operators of
conducting field strength measurements around each antenna (as these
are very costly).
In ProMan the user can define the thresholds for electromagnetic fields
for different frequency bands.
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Specification of
thresholds
for different frequency bands
(for each country individually) |
Specification of the thresholds
for one frequency band
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Individual thresholds (for different frequency bands) can be defined
for each country individually to adpat ProMan to the different national
and international EMC standards.
Based on a mathematical description of wave
propagation phenomena (for each antenna site), ProMan is superposing the
radiation from all antennas in the selected frequency band.
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Superposition
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Exposure
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The figure
shows the superposition of the electric field
radiated from two GSM 1800 antennas on the top of a building.
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With
respect
to the
national thresholds of Germany (in the GSM frequency band) this leads
to the exposure plot (also generated by ProMan).
The exposure in the red marked area is too high (with respect to the
German thresholds). |
The EMC module (NET-E) is an
add-on to ProMan to gerenate
these EMC related results, considering all sites
in the network.
For a GSM 900 network in a city center this leads to the following
results for the superposed electric field strength (all sites in the
GSM 900 band were superposed) and for the exposure (relative to the
national thresholds):
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Superposition
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Exposure
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The
figure
shows the superposition of the electric field
radiated from two GSM 900 antennas mounted at the wall of a building in
a dense urban scenario.
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With
respect
to the
national thresholds of Germany (in the GSM 900 frequency band) this
leads
to the exposure plot . |
As shown above, the EMC results are visualized in a convenient
way
allowing the simple comparison to the defined radiation limits. These
national and international EMC specifications (limits) and standards
can be used to verify the radiation of the antennas
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Features of EMC Module in ProMan
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- Based on highly accurate propagation models (either
deterministic or empirical).
- Unlimited number of antennas can be considered.
For each antenna the following parameters are used for the EMC anylsis:
- Path loss prediction
- Antenna pattern incl. azimuth and downtilt
(already included in path loss prediction)
- Max. radiated power
- Nr of carriers and for each carrier
- carrier frequency / frequency band
- bandwidth
- EMC-Specifications (national or international)
- User-defined thresholds (equations) for
different frequency ranges / bands
- Predefined specifications for several
countries (e.g. Germany, Italy, Switzerland, Austria,...)
- Open interface to define new specifications
or to modify pre-defined specifications
- Wireless standards (analyzed systems)
- Range of the carrier frequencies
- Predefined standards (GSM900, GSM1800,...)
- Open interface to define new standards or to
modify pre-defined standards
- Computed and predicted results:
- Field strength (V/m) for each wireless
standard (superposition of all carriers of the same standard)
- Resulting exposure plot: Superposition of all
wireless standards present in the given scenario (points with field
strength above and below specified threshold are marked).
If you need further information related to these modules please contact us.
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Prediction
on the surfaces of
walls
in an urban scenario.
This is very
important for
EMC & ICNIRP analysis.
(click to enlarge).
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for
WinProp's EMC & ICNIRP module
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Different
operators, regulation authorities,
and public institutions are using ProMan
to investigate the EMC and environmental
scenario in the whole network with (multiple) antenna sites by
comparing the superposed radiated field strength levels to the
specified exposure limits defined in different specifications.
This is
very useful if new antennas are installed on locations where already
multiple antennas are mounted because the probability to obtain field
strength levels above the thresholds is higher the more antennas are
involved.
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