Non-Invasive SAR Using OTA Measurements and Numerical Post Processing

In recent years, the use of wireless devices has increased significantly. Such devices must comply with human safety regulations, and a key parameter is the assessment of the specific absorption rate (SAR). Several methodologies can be used to assess SAR; the reduction of testing time and achievable accuracy are crucial parameters. Recently a Non-Invasive SAR evaluation technique based on passive Near-field measurements and numerical assisted post-processing has been studied and validated for a connectorized radiating element. In this paper this technique is applied to Over The Air (OTA) measurements combined with post processing and numerical simulations of a Golden Wireless Device (GWD). SAR measurements performed with a standard legacy SAR system have been compared with the proposed technique showing a good agreement. These results validate the approach and confirm the applicability of Non-Invasive SAR as a faster alternative for pre-compliance SAR measurements for modern day communication devices.

I. Introduction

Non-invasive Fast SAR techniques have been an area of interest since the arrival of 4G in the market [2],[3]. The legacy systems (e.g [4]), with a single probe sequentially scanning a liquid inside a phantom to evaluate the maximum E-Field and then the SAR around this hot-spot, require a relevant measurement of time.