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.
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.
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 duration||continuous for 6 min|
|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.|
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.