Near-field Radiation from Commercial Cellular Phones Using a Tem Cell

A technique to characterize the fields generated by a cell phone, and projected into an area inside a TEM cell for possible biological interaction studies is described. A double-ended monopole antenna is proposed as the lead signal inducer between the inside and the outside areas of the TEM cell. The coupling voltage at the TEM cell ports and the field distribution within the area under test (AUT) were found to be a function of the phone position, polarization, and dialing type. The measurements for a GSM 850 MHz cellular phone showed that the optimum setup is achievable when the phone is placed outside the TEM cell and co-polarized with the signal leader. An improvement of the field uniformity is possible with the use of a shorter signal leader but at the cost of decreased field strength. The proposed setup can be utilized in studies and experiments related to the radio frequency effects on biological cells and organs.