通信基站室内电磁辐射分布研究

发布时间：2018-04-13 19:37

本文选题：窗户 + 墙壁　；参考：《湘潭大学》2017年硕士论文

【摘要】：近年来,随着通信技术的迅猛发展和手机的大量普及,兴建了大量移动通信基站,加大了环境中电磁辐射暴露水平,人们对此产生了广泛的担忧。大多时间人们都呆在室内,因此精确预测基站周边室内环境中的电磁辐射强度具有很大意义。然而目前的室内辐射预测方法仅仅只是考虑建筑物损耗,并把建筑损耗当做固定值来处理。在实际情况中,房子一般都有窗户,由于窗户的存在,会导致室内的电磁辐射分布发生巨大变化,靠近窗户的地方其辐射肯定比远离窗户的地方要大,另外电磁场在穿过墙壁时还会发生折射和反射,建筑物墙壁材质不同会导致室内电磁辐射强度有很大的差异,当前的预测模型很难对室内电磁辐射分布进行准确预测。针对目前存在的问题,本文主要内容及创新工作如下:(1)对于建筑物窗户面向通信基站场景,本论文提出了一种基于基尔霍夫衍射模型来预测室内电磁辐射分布的方法。该方法首先通过弗林斯传输公式并结合基站的发射功率、增益、距离等信息,计算室外基站辐射传播到建筑物窗户面上某点位电场的幅度,然后把基站发射天线作为初始相位的参考点,通过发散球面波的表达式,计算出窗户面上相应点位电场的相位,接着将窗户看做一个衍射孔径,采用基尔霍夫衍射模型,预测室内任一位置的电磁辐射强度,最后将本文的预测值与实际测量值以及原有的模型相比较。从评价结果表可以看到本文提出的预测方法在离窗户2米时的偏差、精度和相关性分别为0.0138、1.09、0.933,而M Yang的方法只有0.049、0.088、0.661,说明了本文提出的室内预测方法预测效果相比M Yang的方法有了较大的提高。(2)对于建筑物墙壁面向通信基站场景,本论文提出了一种基于穿透理论模型来预测室内电磁辐射分布的方法。该方法首先计算出室外基站辐射传播到建筑墙外的电场强度值,再根据建筑物与基站的位置信息、建筑的墙壁材质计算出基站与墙壁的入射角、特征阻抗、传输系数等相关参数,最后采用穿透理论模型,预测出室内的电磁辐射分布情况,并将测量结果与预测值以及原有的模型进行比较。从评价结果表可以看到本文提出的预测方法在2s方向上的偏差、精度和相关性分别为-0.008、0.0061、0.94,而HP Neitzke的方法只有-0.023、-0.022、-0.83,说明了本文提出的预测方法能够实现更加精确的辐射预测。
[Abstract]: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, increasing 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 around the base station.However, the present indoor radiation prediction method only considers the building loss and treats the building loss as a fixed value.In reality, houses usually have windows, and because of the presence of windows, the distribution of electromagnetic radiation inside the room changes dramatically, and the radiation is definitely greater near the window than in the place far away from the window.In addition, the electromagnetic field refraction and reflection will occur when passing through the wall, and the different materials of the building wall will lead to great differences in the intensity of indoor electromagnetic radiation. The current prediction model is difficult to accurately predict the distribution of indoor electromagnetic radiation.Aiming at the existing problems, the main contents and innovations of this paper are as follows: 1) for the scene of building windows facing communication base station, this paper proposes a method based on Kirchhoff diffraction model to predict the distribution of indoor electromagnetic radiation.The method first calculates the amplitude of the radiation propagation of the outdoor base station to a certain point electric field on the window surface of the building through the Frings' transmission formula and the information of the base station's transmitting power, gain, distance, etc.Then the base station transmitting antenna is taken as the reference point of the initial phase, and the phase of the corresponding electric field on the window surface is calculated by the expression of divergent spherical wave. Then the window is regarded as a diffraction aperture, and the Kirchhoff diffraction model is used.The electromagnetic radiation intensity of any position in the room is predicted. Finally, the predicted value is compared with the actual measurement value and the original model.From the evaluation results table, we can see the deviation of the prediction method proposed in this paper when it is 2 meters from the window.The accuracy and correlation are 0.01381.09 / 0.933, respectively, while the M Yang's method is only 0.049-0.08880.661. it shows that the prediction effect of the indoor prediction method proposed in this paper is much higher than that of M Yang's) for building wall facing communication base station scene.In this paper, a penetrating theory model is proposed to predict the electromagnetic radiation distribution in the room.Based on the position information of the building and the base station, the incident angle and the characteristic impedance of the base station and the wall are calculated according to the location information of the building and the base station.Finally, the transmission coefficient and other related parameters are used to predict the electromagnetic radiation distribution in the room, and the measured results are compared with the predicted values and the original model.From the evaluation result table, we can see the deviation of the prediction method in the direction of 2s, the accuracy and the correlation are -0.008 ~ 0.0061n ~ (0.94), respectively, while the HP Neitzke's method is only -0.023 ~ (-0.022) ~ (-0.83), which shows that the prediction method proposed in this paper can achieve more accurate radiation prediction.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN929.5

【参考文献】