30 gesunde junge Männer (18-30 Jahre) nahmen an der Studie teil. Jeder Proband wurde ingesamt 10 Nächte, jeweils eine Nacht im Abstand von etwa zwei Wochen, untersucht. Die erste Nacht diente der Anpassung und für Screening-Zwecke, die restlichen 9 Nächte wurden aufgezeichnet. Während dieser 9 Nächte wurden die Probanden dabei nach einem randomisierten Design je drei Nächten bei einem GSM-Feld oder WCDMA/UMTS-Feld exponiert oder schein-exponiert.
a head-worn antenna with textile cushion fed by a thin RF coaxial cable was used and attached to the right side of the head during sleep; only RF immune devices were used in the exposure room, other equipment like clocks, portable players and phones were not allowed
RF electric field strengths in the study room were below 0.2 V/m; low frequency electric and magnetic field strengths were 1.0 V/m and 50...70 nT at 50 Hz (utility grid), and 0.6 V/m and 22 mT for other frequencies, respectively; SAR measurements and calculations agreed within 3%; calculated SAR values for the SAM and the Visible Human head model agreed within 20%; consequences of slight variations of the antenna position were calculated as less than 2%
Mess- und Berechnungsdetails
the SAR measurements were performed using a Specific Anthropomorphic Mannequin (SAM) head phantom, calculations in the SAM model and visible human head were done using Finite Difference Time Domain simulations; the antenna achieved similar SAR distributions as published for mobile phones with integrated antennas
1966 MHzcarrier frequency with Quadrature Phase Shift Keying (QPSK) modulation and a power control emulation sequence repeated every minute; the sequence comprised 45 s of toggling between 50% and 100% maximum output power for 0.67 ms each and 15 s of simulated fading over a dynamic range of 30 dB
SAR measurements and calculations agreed within 22%; calculated SAR values for the SAM and the Visible Human head model agreed within 20%; consequences of slight variations of the antenna position were calculated: a deviation of the rotating angle of 15° lead to a SAR change of less than 17%, a 2 mm increase of antenna distance from the head surface resulted in a SAR change of 9%