Mitigation of Mobile Radio Parasitic Radiation Effects: A Review

Abstract

ABSTRACT

In this paper, mitigation techniques useful for improving mobile radio systems power efficiency and decreasing electro-smog and specific absorption rate (SAR) induction, affecting human head and body, are presented. An analysis of main radiation effects from far field base stations and review of mitigation techniques for enhancing the efficiency of power transmission for mobile radio systems is shown, followed by an investigation of the complex radiation field components from operating headsets. The importance of the SAR expression is revealed, considering that the power density level does not really matter under near field complex propagation conditions. Mitigation techniques are suggested to improve the power efficiency especially for headsets by decreasing the SAR, affecting headsets user’s head and body. The efficiency of mitigation techniques for usual headsets using an auxiliary antenna or a special space separation method is discussed. It is shown that small physical or multi-bands low SAR and power efficient headsets can be realized using high dielectric substrates and/or polarization diversity. Recent novel mitigation techniques are proposed for small headsets using metamaterial or metacloak fractal antennas, allowing MIMO applications. Different efficient numerical simulation methods, allowing computing the SAR from different headsets, are compared.

Keywords: Radio systems power efficiency, Base stations, Near-field propagation effects, Headsets performances mitigation techniques, Parasitical radiation reduction, SAR simulation methods