A smart mobile handset plastic case with integrated split ring resonators to reduce SAR

Majority of mobile phones use GSM band (900 and 1800 GHz), GPS band (1.5 GHz) and WiFi band (2.4 GHz). However, most modern mobile handsets can also communicate at another WiFi band which is the 5 GHz band. A plastic smart case with three integrated Split Ring Resonators (SRR) is proposed to reduce SAR (Specific Absorption Rate) of a mobile handset at 5 GHz by mounting this case onto the phone. The radiated EM (Electro-Magnetic) field from the handset antenna interacts with the SRR layer and re-radiates into the far-field. SRR layer directs the radiation away from the handset screen and hence it reduces the human head exposure to the EM field during a call. It is observed that the smart case can reduce the 10 g SAR from 2.49 W/kg to 1.78 W/kg (≈30% reduction) to comply with the SAR limit guideline.