Feasible methods for the evaluation of the specific absorption rate and the temperature rise in the human eyes

Abstract

We propose two feasible methods for the evaluation of the maximum specific absorption rate (SAR) in the human eyes due to exposure to radio-frequency (RF) fields. The methods are applied to the case of near-field exposure to handheld devices; however, they are applicable to the case of far-field illumination as well. The first method is based on a semi-analytical model of the eye. As an input, it requires the measured or simulated open-space field of the device under test. As an output, depending on the mutual position and orientation of the eye and the device, it produces the maximum SAR value in the eye averaged over 1 and 10 grams of tissue. The second method is based on measurements. It requires the fabrication of a simple eye phantom and relies on a standard measurement with an SAR robot. The measurement method is complementary to the semi-analytical model and can be used to verify its output through one additional field measurement in open space. We also develop a detailed simulation eye model, which allows for the calculation of the temperature rise in the eyes for a given device under test. The proposed methods allow for the fast and reliable SAR evaluation of newly developed handheld devices in an industrial environment.