Research On Broadband Electromagnetic Dipole Antennas

With the rapid development and application of mobile communication technology,all kinds of mobile communication systems require the current mobile communication antenna to meet the network requirements of 2G,3G and 4G simultaneously.With the increasing number of users and the coexistence of network,the number of base station antennas is increasing and the structure is more compact.Therefore,people have higher requirements for base station antennas which are capable of supporting broadband and miniaturization of multiple networks.Since the invention of the radio,dipole antenna has been widely used in the field of communication because of its simple and efficient features.The electric dipole and the magnetic dipole can realize the complementary superposition of the E surface and the H surface radiation pattern,and reduce the size of the antenna structure,so that the antenna has a stable direction in the E surface and the H surface.Therefore,the dipole antenna becomes the research hotspot of base station antennas.In this paper,the research work of electromagnetic dipole antenna mainly includes the following aspects:(1)First,the fundamental theoretical knowledge of electric dipoles,magnetic dipoles and electromagnetic dipoles 1s introduced.Then a new wideband electromagnetic dipole antenna structure proposed by Prof.Luk is modeled and simulated.Finally the performance of a wideband electromagnetic dipole antenna is analyzed.(2)On the basis of the antenna structure proposed by Prof.Luk,by improving the horizontal electric dipole,a new hexagonal open resonant ring(SRR)structure is opened in the relative position of two horizontal electric dipoles,and a new type of broadband electromagnetic dipole antenna based on SRR is designed.The antenna has an impedance matching bandwidth of 1.7GHz?2.87GHz(VSWR<1.5),a relative bandwidth of 51.2%,and a stable gain and radiation pattern in the entire working band.which satisfies the requirements of the small size,wide band and high gain of the base station antenna.(3)On the basis of the previous research,an electromagnetic dipole antenna loaded by a short circuit bridge is proposed.By loading a short circuit bridge structure between the two dipole antennas,a frequency resonance point is added to the antenna and the antenna's working bandwidth is increased.The newly designed antenna work band broadened to 1.71 GHz?2.92 GHz(VSWR<1.5),with a relative bandwidth of 52.6%.The antenna has a smaller cross polarization,a higher gain and a stable direction map on the E and H surfaces.It realizes the urgent need of modem communication system for base station antenna multi network system,miniaturization and high stability.