Analysis Of Electromagnetic Radiation Environment Of Antennas

With the development of the technology and the widely use of various antennas, the electromagnetic radiation, caused by the antennas, has been concerned about by many people. This paper, aiming at the problems which was caused by the electromagnetism radiation pollution projects in Beijing in recent years during the process of evaluating, taking the two specific projects carried out by the State Administration of Radio Film and Television and the Beijing Mobile Corporation into consideration, starting from the actual characteristics of the antennas in our country, the author uses the basic theories of electromagnetic field and electromagnetic wave to have deduced calculating models for electric field strength around the medium-wave antennas, the short wave antennas and the antennas for mobile communication. Besides the calculating models are tested and verified by actual measured data, the influence factors to the shortwave antenna, such as frequency and conductance, have also been researched. The electromagnetic interference has been analyzed as well on the basis of the actual condition.Based on the computational value and the actual measured data, we can found that the electric field strength or the power density strength around the medium-wave antenna, the short- wave antenna at the same phase and the antennas for mobile communication decreases as the distance away from the antenna increases, first abruptly, and then the decreasing speed slows down. The electric field strength, around the medium-wave antenna which was worked in multi-towers and multi-frequencies model, decreases as the distance away from the antenna increases, first abruptly, and then the decreasing speed slows down. At the same time, based on the computational value and the actual measured data, it can be drawn that the electric field strength distribution of the shortwave antenna can be influenced by the frequencies and the conductance. The higher the frequency is, the electric field strength is bigger and the decrease speed is quicker. On the contrast, the electric field strength decrease with the increase of the conductance slowly. Besides that, the result showed that the television and telephone of the residents near the antennas have been interfered by the High Order Harmonic which was deduced by the shortwave, especially to the TV programs at relatively lower frequency. The methods to restrain the interference should be concerned through the interference source, pipeline and the equipments which have been interfered.It is feasible to predict and analyze the electromagnetic environment of the medium-wave antennas, short-wave antennas at the same phase and the antennas for mobile communication by using the calculating models respectively in this paper. The error is relatively small and the research has practical significance for the evaluation of the effect brought about by the electromagnetic environment around the antennas, which is concerned about in the environmental protection area in life.