A Study Of Antenna Radiation And Its Wave Propagation Characteristics In Typical Building Environment

The rapid development of broadband cellular mobile communication technology has made a higher requirement for the miniaturization and high performance of the cellular base station antenna,which behaves as low profile,wide impedance bandwidth,low cross polarization,low back radiation,stable gain,3d B bandwidth and symmetrical direction.On the other hand,the working environment of the antenna mentioned above is becoming increasingly complex,the buildings will be the typical working environment of the hotspot base station antenna.From the basic principle of electromagnetism,the propagation of the electromagnetic wave in the environment of the buildings is very different from that in the open environment.It is of great value for the design of broadband cellular mobile communication system to research and understand these differences.In this paper,we mainly discuss the design method of electromagnetic dipole antenna with characteristics of low profile,wide bandwidth,dual polarization and so on.Besides,we also discuss the antenna radiation characteristics in typical building environment.The author's major contributions are outlined as follows: First of all,the principle and related technologies of broadband antenna and the measurement of the characteristic of antenna are summarized.Secondly,a novel four-port electromagnetic radiating elements are proposed.With ideal feeding,the radiating elements achieve good performance such as high gain,low back radiation,sysmetric radiation pattern and so on.Thirdly,a new differential electromagnetic feeding network is designed,and this feeding network has a characteristic of well power division,180 degree phase shift and wide band.Then,an antenna model is proposed by cascade connecting feeding network and radiating elements.The key parameters of the model are studied for achieving good impedance matching and radiating performance.Then,the designed antenna is presented and measured.According to the measurement results,the antenna array achieves a good performance along with a great agreement between measurement and simulation,which verifies the validity of the design method.Finally,we compare and research the new-type EM-dipole antenna in typical environment buildings,obtain the electromagnetic characteristics of high efficiency analysis method and conclusion.