Study On Electromagnetic Radiation Pollution Characteristics And Control Of Mobile Base Station

Mobile base station is an important segment of modern communication network worldwide. Electromagnetic wave emitted from the base station may produce electromagnetic effects in the environment. In recent years, mobile communication industry has rapidly developed in China and resultantly the electromagnetic radiation problems increased in the environment, which attract enormous public attention. Thus, it is considered necessary to study the electromagnetic radiation pollution characteristics and control measures in mobile base stations.The main contents of this paper are as follow:(1) Radiation characteristics analysis of 2G,3G and 4G mobile communication system and base station. Improvement of the spectrum utilization rate, mobile communication system can increase the system’s capacity and also enhance the data transmission rate. But the foundation is still cellular network structure, and the applications of electromagnetic wave loading and transfer information.(2) Helium balloon monitoring technology and the electromagnetic field intensity data near the antenna area are obtained and the changing rule is analyzed. The results revealed that with the increase of distance in front of the antenna, the power density in inverse square distance decreases simultaneously. There is no significant difference of the electromagnetic environment effect on the distribution and severity, while the base station running 2G,3G and 4G networks. Because the electromagnetic field value near the antenna exceeds the limit, so it needs to set up an electromagnetic control distance. At a distance of about 5 m～15 m from the antenna, monitoring data can be in accordance with exposure limit (40 W/cm2) of GB8702-2014 for public; at about 10 m～25 m, the monitoring data can be in accordance with limit (8 W/cm2) of HJ/T 10.3-1996 for a single project management. The distance in front of antenna in all networks running in three base stations increased with the decreased power density. At a distance of about 10 m,15 m and 15 m in front of the antenna, the monitoring data can in accordance with the public exposure limit (40 W/cm2) of GB8702-2014. However, the power density values were much lower than the limited value on the ground, and closed to the background value of the electromagnetic environment of the ground. So, there was no need to set the control distance on the ground. According to limit of a single base station, electromagnetic control distance for the typical mobile communication base station is 25 m right in front of the antenna.(3) A base station running as an analysis object, the researcher need to verify the necessity and rationality of electromagnetic control distance in front of the base station antenna. The results demonstrate that the electromagnetic control distance in the front of the antenna did not retain enough, which resulted in increasing the power density value of monitoring point from the limit. Also analyzes the applications of electromagnetic control distance from the proposed site surrounding situation and structure of antenna.