Adaptive antennas

6 minutes that polarise opinion

To operate adaptive antenna array systems the way they were intended, the limit value is now averaged in six-minute intervals, as is standard in environmental law for other types of exposure. Not everyone is happy about this and outline alarming scenarios, often making spurious comparisons.

Hand on hotplate

Previous assessment methods led to a massive overestimation of the exposure from adaptive antennas. After more than two decades, therefore, the assessment rules have now been adapted by the Federal Council at ordinance level. This is the only way these antennas can play their trump card: reducing total exposure while still transmitting more data. For this purpose, the installation limit value is now averaged over 6 minutes, as has always been the case with the 10-times less stringent exposure limit value (the difference between the installation and exposure limit value is explained below).

Critics like to compare the 6-minute average value with a hotplate: if you hold your hand on a scorching hot hotplate for 36 seconds and then cool it on an ice pack for ten times as long, the mathematical temperature average would be too low to cause a burn. In reality, however, you would still suffer a painful burn. But this comparison is flawed.

In the field of mobile communications, the Swiss installation limit value of 5 volts per metre is far below the internationally recommended 50 volts per metre and very far from causing a harmful thermal effect – in contrast to a hotplate, which clearly exceeds the skin burning threshold.

Comparisons like these are plainly alarmist. So let’s look at how the thermal effect of mobile signals is classified. To prevent it occurring in the first place, the international limit value includes a protection margin with a factor of around 7 to 8. This means that the maximum permissible transmission power of an antenna is around 50 times lower than would be required to have a thermal effect on the body. Scientists specify this as a permanent temperature increase of more than 1 degree Celsius.

Stone-cold hotplates in Switzerland

Switzerland has gone even further, requiring the field intensity to be further dialled down by a factor of 10 at places of sensitive use. This means, in turn, that our antennas have to be 100 times less powerful. If you consider this in terms of the thermal effect explained above: there is around 5,000 times less power in Switzerland than would be required to cause such an effect.

Sensitive locations are classed as places where people tend to remain for longer periods. To go back to the original analogy: our hotplates do not even become lukewarm even when in continuous use.

The international exposure limit applies for all other places, where people do not linger. This average value has existed since the beginning of mobile communications.

If we were to follow the hotplate argument of the mobile technology detractors to its logical conclusion, there would be a statistically significant higher incidence of illness in surrounding countries than in Switzerland. But this is not the case. Even without the more stringent Swiss legislation, the people in these countries are already well protected by the international limit value. A protection margin also applies in Switzerland for mobile phones, which are used in close proximity to the body and account for more than 80% of daily exposure, although this is ‘only’ a factor of 10.

Ordinance on Protection from Non-Ionising Radiation (ONIR)

Protection against electromagnetic fields is regulated in Switzerland in the Ordinance on Protection against Non-Ionising Radiation (ONIR). This ordinance defines the maximum permissible field intensities over a range between 0 Hz and 300 GHz. The federal government enacted the ordinance in 2000. Enforcement is the responsibility of the cantonal and communal authorities: the municipalities are generally responsible for building permits for installations within building zones, and the cantons for building permits outside. The cantons often check ONIR conformity even if the site is located within a building zone, especially if there is a lack of specialised personnel in the municipalities (Source: FSM Swiss Research Foundation for Electricity and Mobile Communication(opens in new tab))

The ONIR in detail: in new tab)

How is a 5G antenna constructed?

Deutsche Telekom in Germany provides a good explanation: in new tab) (German only)


Installation limit value: 

Applies in places of sensitive use and is ten times more stringent that the international limit values. The installation limit value in this form applies only in Switzerland. It is unknown in other countries.

Exposure limit value:

This value is based on international standards and has always been applied in Switzerland wherever there is no installation limit value.

Places of sensitive use (sensitive locations):

These are places where people regularly remain for longer periods of time.

Examples of sensitive locations:

  • Domestic homes (and holiday homes)
  • Classrooms and nurseries
  • Patients’ rooms in hospitals, retirement and care homes
  • Hotel rooms
  • Permanent workplaces (*1)
  • Children’s playgrounds (if stipulated by spatial planning law)
  • School yards and nursery play areas, if used as children’s playgrounds
  • Land zoned for building

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