The interaction between the antenna of the mobile terminal and the body of the user holding it constitutes the main research objective of this project. More specifically, in the framework of the project, the mechanism and the parameters of this interaction are studied in detail. The aim is the evaluation of the handheld antenna performance degradation and on the other hand the determination of the amount of the RF power absorbed in the human body. The derived results can be used in the optimization of the design and development of new more efficient handheld antennas and on the other hand, respectively, these results can be used to evaluate potential health effects or compliance with appropriate standards. A theoretical EM model has been developed, evaluated and optimized with measurements data that will derived through a measurement procedure using prototype measuring setup especially developed for this purpose. The measurement methodology is based on far field EM radiation measurements conducted in the anechoic chamber of the Institute using prototype models of mobile phones and phantom-heads, simulating the electromagnetic behavior of the human head in the vicinity of a radiating handset.