Analysis of SAR Levels in Human Head Tissues for Four Types of Antennas with Portable Telephones

In this paper, a comparative study of several antennas commonly used in portable telephones is investigated. These include a monopole, a helix, a patch and a PIFA antenna. Each one of these structures is modeled and numerically tested using finite-difference time-domain (FDTD) method by using CST Microwave Studio. The testing procedure involves antenna simulation in the proximity of the human head and hand. The behavior of each antenna is evaluated for variable distances from the head geometry (0 - 20 mm). The simulation outputs used as measures for this comparative study include the specific absorption rate (SAR). The computed SAR levels within each of the considered tissues vary for the four antennas under investigation and are within the determined health safety standards. Results suggest that the patch antenna may be the structure of choice when considering safety standards, as its radiation yields the lowest local SAR in the head tissues.