A Parallel Study of SAR Levels in Head Tissues for Three Antennas Used in Cellular Telephones: Monopole, Helix and Patch

Abstract

This paper is a comparative study of several antennas commonly used in cellular telephones. These include a monopole, a helix-monopole and a patch antenna. Each one of these structures is modeled and numerically tested using finite-difference time-domain simulation and human models based on magnetic-resonance images, which allow for inclusion of details of the human body in the simulation. The testing procedure involves antenna simulation in the proximity of the human head. The behavior of each antenna is evaluated for variable distances from the head geometry (0, 1, 2, 4, 8 and 16 mm). Continuous waveform, representative of the sources used in mobile telephones, (250 mW, 1.8 GHz) is used as the form of the antenna excitation. The simulation outputs used as measures for this comparative study include transmitting and receiving antenna characteristics and the specific absorption rate (SAR). The SAR levels for the head tissues are calculated for and with accordance to the two currently accepted standards: Federal Communications Commission (FCC) and International Commission on Non-Ionizing Radiation Protection (ICNIRP). The computed SAR levels within each of the considered tissues vary for the three 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.

FEM modeling of SAR distribution and temperature increase in human brain from RF exposure

“…Interaction of handset antennas with the human body is a great consideration in cellular communications. Simplified phone antennas such as half‐wavelength dipoles in free space or quarter‐wavelength monopoles mounted on a metallic box have been frequently investigated in the literature. These antennas are no longer in widespread use for cellular phones and therefore it is not suitable to use them for studying the interaction of handset antennas and nearby tissues.…”

Simulaciones de tasa de absorción específica (SAR) de cuerpo completo sobre un esferoide prolato utilizando diferentes polarizaciones de onda plana hasta 100 GHz

“…Once the reflection coefficients are obtained, the transmission coefficients for each patch are calculated using equations (9) and (10).…”

Performance analysis of a planar inverted-F antenna (PIFA) including human interaction

“…Comparison of these results yields that the handsets with built-in antennas are much less sensitive to how the phone is held than the handsets with external antennas. The patch antenna produces the lowest SAR in the head tissues than monopole and helix antennas operated at 1.8 GHz [5].Multiband fractal planar inverted F antenna (F-PIFA) is designed and its performance is analyzed for mobile phone application [6].…”