Antenna Behaviour in the Presence of Human Body

Abstract – Mobile phones are widely used nowadays. The demand in the new generations of mobile phones is better performance. Typically the mobile phone performance is derived assuming an ideal antenna impedance of 50Ω. Some work has been done in understanding the behaviour of the antenna impedance in a real environment [1], [2], [3]. This work continued the exploration of the difference between the ideal antenna impedance and the antenna impedance in a real environment. In particular the analysis was carried out measuring the antenna impedance in presence of the human body and relating it to the position of the hand and of the hand + head. Two types of antennas were considered: PIFA antennas and ceramic antennas. Several positions of the hand and of the hand + head were considered. These positions were selected after an accurate study about how people on the street normally handle their mobile phones. The study consisted of two steps: 1) observation of the typical positions of the hand and of the hand + head with respect to the mobile phone; 2) their imitation in the lab for the measurements The outcome of the investigation was the changing of the impedance is primary due to a changing of its imaginary part. The real part is affected but not in dramatic way