Effects of Electromagnetic Absorption Towards Human Head Due to Variation of Its Dielectric Properties at 900, 1800 and 1900 MHZ With Different Antenna Substrates

Abstract

Abstract-This paper analyzes and discusses the effect of the electromagnetic absorption by human head against variation of head dielectric properties at 900, 1800 and 1900 MHz. The characteristics of helical antenna and its substrates with variation in human head dielectric properties are simulated by implementing finite-difference time-domain (FDTD) method using CST Microwave studio. The variations in human head dielectric properties were manipulated by increasing and decreasing 10% and 20% of each of the human head dielectric properties. In this paper, SAR values increase with increment of head conductivity, and increment of head permittivity and head density lead to decrement of SAR values. Helical antenna with substrate of FR4 results in higher SAR values in all frequency exposures. The head SAR values are higher with higher frequency exposures. The helical antenna with substrate of Rogers RO3006 (loss free) is found to be better over FR4 and Rogers RO4003 (loss free), which contributes towards much lower SAR values in all GSM frequency bands exposure.

Investigation and reduction methods of specific absorption rate for biomedical applications: A survey

“…The drawback of this model is the shape and size of the Ear changes and evaluation done on a particular phantom with dipole antenna is added disadvantage. Husni et al analyzed the effect of metallic earing on antenna performance and have observed peak SAR increases due to field scattering, and redistribution of RF energy occurs. The dipole antenna without shielding is again a setback in this analysis.…”

Characteristics of a planar metal antenna in vicinity of human head at 900 MHz and 1800 MHz

“…The permittivity, conductivity and mass density of the homogeneous human head at 900 MHz and 1800 MHz are given in Table 2 [7]. To consider the effects of head the antenna is placed at a certain distance (say S mm) from the head as shown in Fig.…”

“…It is usually averaged either over a small volume of tissue (1 g or 10 g) or over the whole body. In USA, the SAR limit is specified as 1.6 W/kg, averaged over 1 g of tissue and in Europe and Japan, the SAR limits are specified as 2.0 W/kg, averaged over 10 g of tissue [7]. In [8] SAR evaluations of a dipole antenna for different frequencies are shown and compared with the safety limit.…”

A New Design of Metamaterials for SAR Reduction

“…There are various sources of uncertainty and variation in this kind of combined FDTD and temperature simulations [5][6][7][8][9][10][11][12][13][14][15][16]. Usually, the rise in temperature has been small so thermoregulatory response has been ignored, which may have led to overestimation.…”