Reduction of Peak Sar in Human Head for Handset Applications With Resistive Sheets (R-Cards)

Abstract

Abstract-In this paper, reduction of peak specific absorption rate (SAR) for handsets with monopole type antenna through R-cards is investigated. While the numerical analysis was performed using finite integration in time domain (FIT), real measurement has been made to validate the simulation results. Both the simulation and measurement results revealed that a minimum SAR Reduction Factor (SRF) of 60% was achieved. The good agreement between the simulation and measurement results has evidenced the effectiveness of the proposed approach for SAR reduction in human head for handset applications.

Performance study of electromagnetic protective sheets for wireless communication systems

“…It was found that the return loss of the antenna is affected by nearby EM protective sheets. As far as the operating band for the 2.4 GHz WLAN (determined by 11 10 dB S d ) is concerned, the MSHIS-and JCHIS-added antennas can provide a reasonable operating band to cover the desired WLAN band of 2.4-2.484 GHz. However, the operating bands of the metal-plate-added antenna, the R-cardadded antenna, and the RF-absorber-added antenna do not meet the requirement.…”

“…For examples, Sager [10] placed a parasitic radiator (metallic plate) between the PIFA and head to reduce the SAR by 6 dB. Chou [11] achieved a minimum SAR reduction factor of 60% for handsets mounted with a monopole antenna through R-cards, Islam [12] found that the peak SAR of the head can be reduced by placing a ferrite sheet between the antenna and head, Kwak [13] designed an electromagnetic band-gap (EBG) component to reduce the SAR by 43%, and Hwang [14] found that the peak SAR in the head can be reduced by placing metamaterials between the antenna and human head. In our previous study [15], highimpedance surfaces (HISs) were proposed to reduce the interaction between a mobile phone antenna and its user, and to reduce SAR values.…”

Assessment of specific absorption rate reduction in human head using metamaterial

“…Recently, metamaterials, including EBG structures [13], have been proposed for mobile phones with peak SAR descriptions [17]. According to these studies, the overall dimensions of the antennas with metamaterials were larger than those of wireless terminals.…”

“…Although, in principle, the solution for general geometries does not require any additional effort with respect to the standard method, the technique requires the definition of a discretised space by assigning to each cell its own electromagnetic properties, which is not an easy process [13][14][15][16].…”

“…Recently, there are considerable interests in metamaterials with a split ring resonator (SRRS) structure which was proposed to reduce the SAR value [13]. SRRSs are the best known elements of structures that provide a negative magnetic response, and an array of long wires is normally used to achieve a negative electric permittivity [7].…”