Establishment Of Microwave Electromagnetic Radiation Model Based On Visual Human Body And Research On Its Safety

Research shows that when the human body is exposed to excessive electromagnetic radiation for a long time,it may cause potential harm to human health.In view of the current research on electromagnetic radiation safety mostly using a single antenna,in order to understand the distribution and impact of electromagnetic radiation in the human body with multiple antennas in mobile phones under different network standards,this paper uses CST electromagnetic field simulation software to realise microwave electromagnetic radiation modelling and safety research on the visualised human body.The SAR values of the human head are simulated using a visual human electromagnetic thermal model and a mobile phone model consisting of several antenna modules,and the radiation of different antennas on mobile phones to three different head models is systematically analyzed.The simulation results are compared with the standard limits given by the ICNIRP guidelines,so as to realize the safety assessment of human electromagnetic exposure.The main research work of this paper are as follows:(1)A microwave radiation safety simulation model based on the visualized human body is established using CST electromagnetic simulation software,which mainly includes two parts: the mobile phone and the visualized human body.The mobile phone part contains five different network standards(3G/4G/5G/2.4G＿WIFI/5G＿WIFI)and a total of six antenna modules.For the visualized human body part,three different human head models of adult male,adult female,and child are used,and the electrical conductivity and relative permittivity of each tissue in the head are obtained by the fourth-order Cole-Cole model.(2)Firstly,simulate and analyze the SAR distribution of three different heads under the maximum transmit power(corresponding power: 250 m W,200 m W,200 m W,32 m W,32 m W)of the different network standard antennas(corresponding operating frequencies are: 1852.4 MHz,2310 MHz,4400 MHz,2412 MHz,5210 MHz)of the mobile phone.Secondly,the distribution and influence of head SAR when the transmit power is 0.2 W,0.5 W,and 1 W,and when each mobile phone antenna works alone or when multiple antennas work together are simulated and analyzed.Since the mobile phone is the closest to the human body when answering a call,the radiation of the mobile phone mainly acts on the head of the human body.Therefore,this paper mainly analyzes the electric field intensity and SAR distribution of the head in three cases: the distance between the mobile phone and the head,the distance between the antenna and the head,and the angle between the mobile phone and the head.(3)The DASY5 system was used to conduct the experimental measurement of the SAR value of human electromagnetic exposure to verify the correctness of the simulation model.Both simulations and experiments use a standard human head model(SAM model)and two PIFA antennas with frequencies of 2412 MHz and 5210 MHz,and the antenna power are 32 m W.The results show that the maximum spatial average SAR value errors of the experiment and simulation at 2412 MHz and 5210 MHz are 7.1% and 6.9%,respectively,with good consistency,which proves the correctness of the simulation model.All simulation results are compared with the safety limits given by the ICNIRP standard and evaluated for safety.The results show that the radiation to the head from the mobile communication modules are below 1.2 W/kg and the radiation to the head from the WIFI modules are below 0.4 W/kg at the maximum transmitting power,and that the radiation to the head from the antennas of the mobile phone at different frequencies are safe.In terms of power,the electromagnetic radiation absorbed by the head can only be within safe limits if the power of the mobile communication modules are at least below 0.2 W and the power of the WIFI module are at least below 0.5 W.