Novel SAR-reducing add-on cover for MIMO handheld device

In this paper, we present an innovative wave-guiding structure for reducing EM power absorbed by human body. A MIMO handheld device with the proposed wave-guiding structure, constructed of metal patch or photovoltaic panel, can effectively reduce its SAR value. The radiation efficiency and frequency response are affected slightly when the proposed structure is presented. Thus the wave-guiding structure with thin profile can be easily integrated with mobile phone or as an add-on protecting case without modifying the existing antennas. Two types of wave-guiding structures for 2.6 GHz WiMAX MIMO handheld device are constructed and measured. The simulated and the measured results confirm the effectiveness of our proposed SAR-reducing structure.