SAR Optimization

Model

In this joint project, a highly detailed CAD model of a multi-band phone was provided by the manufacturer. The model contained a helical antenna, multi-layer PCB, shielding, display and dielectric housing parts. Freespace and device+head (homogeneous SAM, inhomogeneous head phantom) configurations for both touch and tilt positions were considered.

Simulation

In order to resolve the multi-layer PCB and the curvature of the thin helical antenna, minimum grid resolutions of 0.15 mm were applied. Maximum grid resolutions were also reduced in the area of the head phantom, where high permittivities (approx. 40) occur. Total grid sizes of 6 million cells (freespace) and 14 million cells (device+head) were used.

Results

Significant RF performance and SAR parameters for both GSM and DCS bands were recorded and validated using the DASY4 measurement system. Good to excellent agreement was obtained. This study was the first of its kind in which the FDTD method was applied to a complex CAD model of a mobile phone.
 
For further information related to this study download the publication.