Research On Exposure Characteristics Of 5G Mobile Phone Antenna And Temperature Field Distribution In Human Head

With the rapid development of 5G communication technology,5G mobile phone has gradually entered the public field of vision.Whether the electromagnetic exposure of mobile phone antenna has an impact on human health has been one of the hot topics of the majority of experts and scholars in recent 20 years.In order to study whether the electromagnetic exposure of 5G mobile phone antenna poses a threat to human health,based on the existing research theory of electromagnetic exposure of mobile phone antenna,the exposure characteristics of 5G mobile phone antenna and the distribution of SAR and temperature field in the head model are systematically analyzed by modeling with COMSOL simulation software,and the simulation results are compared with ICNIRP standard for electromagnetic exposure safety assessment.The specific research methods are as follows:1?The antenna model of 5G mobile phone is established through the RF module of COMSOL simulation software,and the exposure characteristics of the antenna are simulated and calculated.The results show that the-6d B return loss bandwidth of 5G mobile phone antenna designed in this thesis can cover the central frequency of GSM-850/900,DCS-1800,PCS-1900,UMTS-2000,Wi MAX-2300,LTE-2300/2500 and the central frequency of 5G mob-ile phone of 3.5GHz.It meets the requirements of 5G mobile phone antenna working in 5G network band and downward compatible with 4G/3G/2G band.2?A three-layer spherical head model including scalp layer,skull layer and brain layer is established by using COMSOL simulation software biological heat transfer module.Based on the bioelectric coupling of electromagnetic field,the distribution of SAR and temperature field of 5G mobile antenna in headform is analyzed systematically,When the mobile phone antenna works in 5G/4G/3G/2G(the antenna operating frequency is 3500 MHz,2600 MHz,1900 MHz and 900 MHz),the input power of antenna is 0.125 W and 0.245 W,and the exposure time is 6 min and 30 min respectively.The simulation results were compared with ICNIRP standard for electromagnetic exposure safety assessment.The main conclusions are as follows:(1)In the human head model,5G mobile phone antenna electromagnetic exposure has the largest SAR value in the scalp layer,the second in the brain layer and the smallest SAR value in the skull layer.When the antenna operating frequency is 1900 MHz and the input power is 0.245 W,the SAR value of scalp layer is the largest,which is 0.715 W/kg.The maximum SAR value accounts for 35.75%of the standard limit,which does not exceed the ICNIRP standard limit.(2)No matter the input power of the antenna is 0.125 W/0.245 W,the exposure time is 6min/30 min,and the working frequency is 1900 MHz,the temperature field in the brain layer of the head model is the largest.When the exposure time is 6 min,the maximum temperature of the brain layer is 37.180 ~oC,and the maximum temperature rise is 0.18 ~oC;when the exposure time is 30 min,the maximum temperature of the brain layer is 37.200 ~oC,and the maximum temperature rise is 0.20 ~oC,and the temperature field rise is far less than the 1~oC thermal damage limit specified by ICNIRP standard.(3)When the mobile phone antenna works in 5G band(working frequency is 3500MHz),the SAR and temperature field of each tissue layer of the head model show a downward trend with the increase of distance.The SAR value decreases relatively fast,while the tempera-ture field changes very slowly.When the distance between the antenna and the head model in-creases from 5 mm to 30 mm,the SAR value decreases by 50.20%,while the temperature field decreases by only 0.18%.3?All the simulation results of COMSOL are compared with ICNIRP standard.The results show that the SAR value of 5G mobile phone antenna in the head model does not exceed the standard limit of 2 W/kg,which is within the safe range.At the same time,the distribution of the temperature field of the headform does not exceed the 1 ~oC thermal damage limit of ICNIRP standard.The results show that the distribution of electromagnetic exposure and temperature field caused by 5G mobile phone antenna is safe and will not pose a threat to human health.The above research work provides a theoretical basis for fully understanding the biological effects of 5G mobile phone antenna electromagnetic exposure on the human head,and has certain application value.