Reduction of the peak SAR in the human head with metamaterials

The electromagnetic interaction between the antenna and the human head is reduced with metamaterials. Preliminary study of SAR reduction with metamaterials is performed by the finite-difference time-domain method with lossy Drude model. It is found that the specific absorption rate (SAR) in the head can be reduced by placing the metamaterials between the antenna and the head. The antenna performances and radiation pattern with metamaterials are analyzed. A comparative study with other SAR reduction techniques is also provided. The metamaterials can be obtained by arranging split ring resonators (SRRs) periodically. In this research, we design the SRRs operated at 900 and 1800 MHz bands. The design procedure will be described. Numerical results of the SAR values in a muscle cube with the presence of SRRs are shown to validate the effect of SAR reduction. These results can provide helpful information in designing the mobile communication equipments for safety compliance.