SAR is a value corresponding to the energy absorbed by human tissue when exposed to radiation. In this study, the SAR value caused by a base station operating at 900 MHz and 1800 MHz independently of the mobile phones was investigated by means of the signal generator that represent the base station. The calculations are evaluated by simulations through the CST STUDIO program for 900 MHz and 1800 MHz, and compared with the actual measurements results that performed at a standardized SAR laboratory. In order to determine the effect of the same SAR value of SAM phantom on human tissue Gustav biomodel was used. The SAM calculations were repeated for Gustav and the 1g and 10g SAR values for 900 MHz and 1800 MHz were calculated. At 900 MHz the SAR value of 0.175244 W / kg obtained in the SAR laboratory was successfully simulated with a SAR value of 0.176615 W / kg obtained in the simulation medium. At 1800 MHz The SAR value of 1.748332 W / kg obtained in the SAR laboratory was successfully simulated with a SAR value of 1.74521 W / kg obtained in the simulation medium. These SAR values correspond to about 13.75 V / m for 900 MHz and 35.50 V / m for 1800 MHz of absorbed electromagnetic field in the phantoms whose dielectric properties are approximately the same.