Interactions between the human body and the personal communications are a nowadays a crucial point. Until now, studies are largely focused on the electromagnetic fields fading due to the head and the body being in the vicinity. However, it has been shown that the impact of the hand has been underestimated. Recent investigations [7], lead on the different user hand grip styles and shapes, give the possibility to examine interactions between hand models and mobile antennas. This thesis intends to investigate the influence of the usual hand-hold position on different dual-band PIFAs antennas using the Finite-Difference-Time-Domain (FDTD) method. The simulation analysis is based on both mismatch and absorption loss providing a comparison of performance for five types of PIFAs. Six hand models are used and different positions of the antenna are investigated. It is shown that the antenna efficiency is significantly altered owing to the hand and finger position. The antenna behaviour is described for all different configurations and some of them present