Evaluation of SAR Reduction for Mobile Phone Using RF Shield

This paper presents the numerical evaluation of the microwave absorption at 2.4 GHz (ISM band) in a homogeneous rectangular head model. Specific absorption rate(SAR) reduction in the head model is achieved by attaching nickel-zinc spinel ferrite sheet resonating at 2.4 GHz to a mobile phone. RF shields made of ferrite sheets are used to suppress surface currents on the mobile phone. Simulations are performed to investigate the effect of various parameters like size, shape and type of the shield on the SAR using CST-Microwave studio, the field simulation software. The SAR is obtained by calculating electric field strength at various points in the head model with and without RF shield. The E-field variation in the head model shows that RF shields reduce the SAR effectively. Numerical results are compared with experimental results from published work. Simulation results will be useful for compliance testing of mobile phones.