Effects of supporting structure on wireless SAR measurement

The effect of the supporting structure for SAR measurements of wireless handsets has been investigated experimentally and numerically. A phone with a quarter wave monopole antenna was used for this investigation. Various dielectric slabs were tested as the supporting structure and configurations that resulted in a significant change in the SAR values were identified. The SAR values were obtained by both measurement and simulation with and without the dielectric support structure. There is good agreement between the measured and computed differences in the SAR values with and without the support in both bands. In the 900 MHz band, the resonance frequency is shifted by 18% and the SAR is reduced by 30%. In the 1900 MHz band, the resonance frequency is reduced by 35% and the SAR is decreased by 56%.