Effects of high frequency electromagnetic field emitted from digital cellular telephones on electronic pocket dosimeters

High frequency electromagnetic fields emitted from digital cellular telephones (cell phones) occasionally cause abnormally high values (wrong dosages) on electronic pocket dosimeters (EPD). Electric field strength distribution around the cell phone transmitting 1.5GHz band with a maximum power of 0.8 W was analyzed by using an isotropic probe with tri-axial dipole antennas. Five kinds of EPDs were exposed to the fields for 50s under four kinds of configurations relative to the cell phone. The electric field distribution expanded around the antenna and had a maximum strength level of 36.5 ± 0.30 V/m. The cell phone gave rise to a wrong dosage of four EPDs out of five. The electromagnetic susceptibility of the EPD was higher in the section where the semiconductor detector or electric circuit boards were implanted. The maximum value of wrong dosage was 1283μ Sv. The distance preventing electromagnetic interference differed in each EPD and ranged from 2.0cm to 21.0cm. The electromagnetic immunity levels of the EPDs were distributed from 9.2V/m to a value greater than 35V/m. The EPDs displayed wrong dosage during exposure, while they recovered their normal performance after the cell phone ceased transmitting. The electromagnetic immunity levels of the EPDs were either equal to or greater than the IEC-standard. The immunity levels should be enhanced greater than the IEC-standard from the standpoint of radiation protection