Study on reduction of specific absorption rate of 2.4 GHz dipole antenna by using novel artificial magnetic conductor's reflector

A reflector, which is by using a novel type of the artificial magnetic conductor (AMC) is designed to reduce the specific absorption rate. Transformed symmetrical mushroomlike surface without via holes in cells focused on 2.4 GHz WLAN band is developed. Therefore the designed AMC structure has a high impedance surface characteristic. Each slot in the designed AMC structure plays a key role in modeling at the desired frequencies. One of The special characteristics is that the antenna on the AMC's reflector is working within a quarter-wavelength. For simulated and measured results, reflection coefficients show similar patterns between the AMC's reflector separated one-tenth-wavelength from the antenna and the PEC's reflector separated a quarter-wavelength from the antenna. The designed structure has broad bandwidth, small size, and is easy to fabricate because the proposed structure has no via holes. The human effect is analyzed with applying the designed reflector to the 2.4 GHz dipole antenna. The calculated peak SAR averaged over 1 g is only 0.168 W/kg, when the input power is 1 W. The results show that over 90% of the SAR is blocked compared with the absence of AMC's reflector.