Study type: Medical/biological study (experimental study)

Measurements of skin surface temperature during mobile phone use. med./bio.

Published in: Bioelectromagnetics 2007; 28 (2): 159-162

Aim of study (acc. to author)

To measure temperature rises on the side of the face after 6 minutes of continuous mobile phone operation using two models of analog mobile phone system phones (operating in the 835 MHz band) and three GSM mobile phone models operating in the 900 MHz band.

Background/further details

Additionally, the temperature on the side of the face for analog mobile phone system phones while it was inoperative, transmitting, and in stand-by mode was measured in order to separate the contributions to heating from the radiofrequency amplifier and control electronics.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 835 MHz
Exposure duration: continuous for 6 min
Exposure 2: 900 MHz
Exposure duration: continuous for 6 min

General information

The tests were performed on three GSM and two AMPS phone models that were in use in the mid-1990s and may not be representative of current designs or battery technologies. If the phone had an extendable antenna this was pulled out during the measurements.

Exposure 1

Main characteristics
Frequency 835 MHz
Type
Exposure duration continuous for 6 min
Exposure setup
Exposure source
Chamber The subject sat on a chair in a semi-anechoic chamber during exposure and warm-up period.
Setup Immediately following a 15 min warm-up period, the phone in test mode transmitting at full power was held loosely with the fingers by the subject against the right hand side of his head and touched the skin in the typical use position for a period of 6 min.
Additional info An additional comparative test was performed with one of the AMPS phones while it was inoperative, transmitting, and in stand-by mode in order to separate the contributions from the RF amplifier and control electronics.
Parameters
Measurand Value Type Method Mass Remarks
power 600 mW mean - - -

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 6 min
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
power 250 mW mean - - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • before exposure
  • after exposure

Main outcome of study (acc. to author)

For the GSM mobile phones the highest recorded temperature rise difference was 2.3°C and for the analog mobile phone system phones it was 4.5°C. The higher differential temperature rise between the two mobile phone systems may reflect the higher maximum average operating power of analog mobile phone (600 mW) versus GSM 900 (250 mW).
Additionally, comparison of temperature changes at a consistent location on the cheek for an analog mobile phone system phone showed that it was -0.7°C for inoperative status (i.e. cooler than the left control cheek side), +2.6°C for transmitting at full power and in stand-by mode +2.0°C.

Study character:

Study funded by

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