Study of the interaction user head-ultrawideband MIMO antenna array for mobile terminals

This paper presents a numerical study of the interaction between the user head and MIMO antenna array for mobile phones. The antenna array is composed of two identical antennas and covers the frequency ranges 698-990 MHz and 1710-5530 MHz with a good radiation efficiency in free space. The two aspects of the interaction are considered: 1) the influence of the user head on the antenna operation, and 2) the exposure of the human head tissue to antenna electromagnetic radiation. The first aspect is related to the degradation of the antenna performance in a proximity to the user which is evaluated by the reduction of the antenna radiation efficiency. The second aspect refers to the antenna operation effect on the human and the exposure of the user head is studied by Specific Absorption Ratio (SAR).