Experimental study of the interactions between terminal antennas and operators

Research on the interaction between terminals and operators concentrates on two major issues, which are directly related to (i) the actual properties of the terminal antennas, and to (ii) the undesired absorption of the radiated energy. The operator proximity as well as the direct contact with the handset, leads to noticeable changes in the electrical performance of the antenna. Of these changes the input impedance and radiation properties are of greatest concern. A considerable portion of the radiated energy propagates towards the operator's body, and a portion of this energy is absorbed by human tissues. A widely recognized measure for this adverse effect is the specific absorption rate (SAR). Since the SAR has become a regulatory issue in many countries, energy absorption must be regarded as a sensitive matter. We show some results of our investigations into variations of radiation patterns and levels due to the interaction with human body.