Research On Multi-polarization Antenna For Wireless Communication

The modern wireless communication system is versatile and supports multiple communication modes,which is caused by the subdivision of wireless communication application scenarios.This subdivision has increased the consumption of spectrum resources and make it increasingly tense,and this problem can be solved by the technology of polarization diversity.This thesis will focus on the study of the multipolarization antenna that is one of the key components and multiplex elements in the diversity system.Besides,multi-polarization antennas can make communication systems have more functions and easily be integrated.The main research contents include:Chapter 1 systematically reviews the development history of the multi-polarization antenna and summarizes the research progress and breakthroughs in multi-polarization antenna in recent years.Besides,it explains the main research contents and contributions of this paper.Chapter 2 introduces the basic theories and analytical methods involved in the research.It mainly includes:(1)the concepts of polarization and basic parameters of antennas;(2)the basic theories of the microwave network,including scattering and transmission parameters and the equivalent circuit parameters of metal lines and slots;(3)the passive microwave components for the feeding network;(4)the principle of polarization manipulation by the anisotropic artificial electromagnetic structures,including the propagation characteristic of planar electromagnetic waves in anisotropic materials and the principle of the polarization manipulation.Chapter 3 proposes a quadri-polarization antenna based on the improved planar feeding network to broaden the effective operating bandwidth that is narrow in traditional multi-polarization antennas.The antenna achieves an effective operating bandwidth of 22.7% in simulation and measurement,and has comparable radiated performance as a typical microstrip antenna.At the same time,the main factors affecting the antenna and the feeding network are analyzed,which provides a reference for improving the design of the feeding network and multi-polarization antenna.Chapter 4 proposes a novel artificial electromagnetic structure basing the anisotropic material properties and the equivalent circuit analysis to solve the problem that cannot obtain four polarized modes in traditionally loaded artificial electromagnetic structures.Both theoretical and simulation results show that the loading structure can indeed make the antenna have ability to manipulate quadruple polarizations.Chapter 5 summarizes the main research contents and innovations of this paper and shows the shortcomings of the current research and plans the future work.