The Indoor Electromagnetic Radiation Distribution Research Of Mobile Communication Base Stations

In recent years,with the rapid development of communication technology and the popularity of mobile phones,a large number of mobile communication base stations have been built,which have increased the level of electromagnetic radiation exposure in the environment.Most of the time people stay indoors,so it is of great significance to accurately predict the electromagnetic radiation intensity in the indoor environment.However,the current indoor radiation prediction methods only consider the loss of buildings on the basis of outdoor prediction,and treat the building loss as a fixed value.In fact,the house generally has a window.As a result,the distribution of indoor electromagnetic radiation will undergone tremendous changes.In addition,there are reflection and refraction in indoor environment,buildings of different wall materials will lead to different intensity of electromagnetic radiation in the room.It is very difficult to predict the distribution of electromagnetic radiation in the current prediction model.For the above problems,the main contents and innovations of this paper are as follows:(1)For building windows facing communication base station,this paper presents a method based on Kirchhoff diffraction model to predict indoor electromagnetic radiation distribution.First,through the Frings transfer formula and combined with the base station's transmit power,gain,distance and other information,calculate the outdoor base station radiation spread to the building window surface of a point electric field amplitude,then,the base station transmitting antenna source point is taken as the reference point of the initial position,and the phase of the electric field of the corresponding point on the window surface is calculated by dispersing the expression of the spherical wave,and then the window is regarded as a diffraction aperture,the Kirchhoff diffraction model is used to predict the electromagnetic radiation intensity at any position in the room,finally,the predicted value of this paper is compared with the actual measured value and the original model.From the evaluation results table,we can see that the deviation,accuracy and correlation of the prediction method proposed in this paper are 0.0138,1.09,0.933,and the method of M Yang is only 0.049,0.088,0.661,which is described in this paper.The predictive effect of the indoor prediction method has been greatly improved compared with the M Yang method.(2)For building walls facing communication base stations,this paper presents a method based on penetration theory to predict the distribution of indoor electromagnetic radiation.First calculate the outdoor communication base station radiation spread to the building wall outside the electric field strength value,and then according to the location of the building and the base station information,building wall material to calculate the base station and the wall of the incident angle,characteristic impedance,transmission coefficient and other related parameters,finally,the penetration model is used to predict the distribution of electromagnetic radiation in the room,and the measurement results are compared with the predicted values and the original models.From the evaluation results table,we can see that the deviation,accuracy and correlation of the prediction method proposed in this chapter are-0.008,0.00161 and 0.94 respectively,and the method of HP Neitzke is only-0.023,-0.022,-0.83,of the prediction method can achieve more accurate radiation prediction.