Loop antenna design for in vivo localized exposure at 2.45 GHz

The large diffusion of wireless networks in houses and public environments as well as the emerging use of VoIP phones has entailed the need of performing biological experiments around the frequency of 2.45 GHz. In this paper, a loop antenna for localized exposure of the head of small animals restrained in special Perspex cages is presented. The antenna design and optimisation for feed and stub positioning was performed with numerical simulations. The optimised antenna was fabricated and experimentally characterized in terms of S₁₁ parameter and SAR distribution in a cubic phantom filled of equivalent biological medium. An excellent agreement between simulation and measurements was found. A good efficiency value (>;10 (W/kg)/W) was obtained in a localized region close to the antenna, where the SAR homogeneity is above 70%.