SAR Reduction

Application

Specific Absorption Rate (SAR) refers to the level of wireless-device-generated electromagnetic radiation that is absorbed into human tissue. The FCC has established firm SAR guidelines for manufacturers of these devices.

Summary

An American handset manufacturer was about to release a new design when it became apparent that the product would exceed the recommended SAR level. The problem was traced to poor contact between the EMI shield and the PCB in a specific area of the handset. Hence, the shield was not properly grounded, resulting in EMI leakage.

Results

The EMI leakage problem was solved by placing a single GORE-SHIELD™ SMT RF grounding pad in the problem area, improving the PCB-to-shield ground. The compliant properties of the grounding pad required the manufacturer to make only minimal changes to the shield to accommodate the new part, and no changes to the overall shielding scheme were required. The SAR was reduced to an acceptable level, and the new design was released on schedule.