Influence on antenna diversity for a handheld phone by the presence of a person

The diversity gain obtained by employing antenna diversity on handheld phones are investigated for the two branch case, both in free space and in the presence of the human head. The envelope correlation coefficient is calculated from measurements of angular distributions of multipath field and complex 3D radiation patterns. The mean effective gain (MEG) and diversity gain is calculated for a 360/spl deg/ rotation of the phone in the environments. Different types of antennas (whips and patches) are investigated in order to see if different antennas are influenced differently by the human head. Results including a model of the human head are compared with results for the handheld in free space. The results show that for both omnidirectional like antennas and more directive antennas the correlation coefficient increase significantly in the presence of the human head and the MEG decrease significantly, but the diversity gain is nearly the same. It is concluded that a model of the user is necessary in optimizing the antenna design for handhelds.