| With the fast development of the advanced wireless communication system,the working band is developing towards the multi-standard and broadband,that the higher requirements are put for the devices of the system.As we all know,antenna is the key component of the wireless system,while the miniaturization,wideband,and easy integration have become the trend of the antenna design.Because of these characteristics,microstrip antenna has attracted extensive research and attention in the world,and has become a hot issue.Therefore,this paper takes high-performance miniaturized broadband antenna as the research topic.This focuses on the realization of broadband performance improvement,the miniaturization of antenna and the design of broadband array antenna.The main content of the research is divided into the following four parts:In the first part,the main parameters of the antennas are introduced.Then the basic theory of microstrip antenna and main analysis methods including transmission line and cavity model analysis are introduced.Then the design of wideband antenna and design method to improve the bandwidth of antenna are introduced.At last,the basic theory of array antenna,the design and selection of feed network and the pattern multiplication of array antenna are introduced.In the second part,the antenna based on the structure of symmetrical two ring slot is proposed.And the equivalent circuit model is proposed on the theory of electromagnetic field and transmission line.The resonant frequencies of the antenna can be obtained by theoretical calculation.The two resonant frequencies can be adjusted by the length of the ring slot and middle connecting line.The equivalent model provides effective guidance for the design of the antenna.The antenna has the advantages of the compact structure and simple design.In the third part,the antenna based on defected ring slot line is proposed.The method is proposed to improve the bandwidth of the antenna by introducing defect structure into the ring slot.The method can also keep the antenna size basically unchanged.At the same time the defected structure and its parameters can be reasonably adjusted to meet the design requirements of bandwidth.This part of the antenna design can cover the 5G band from 20 GHz to 45 GHz.This method can also be applied to the design of the microwave passive circuits and other millimeter wave communication systems.Finally,the antenna structure is processed and measured to verify the correctness of the design.The fourth part presents the broadband array antenna for 5G communication system.The array antenna is based on the defected ring slot antenna.The corresponding wideband power divider and feeding network are designed for the 4,8,16 and 32 elements arrays.The arrangement of the array antenna is compact.The influence of the feeding network on the overall size of the array antenna is reduced.Finally,all array antennas are fabricated and measured,which has wide bandwidth performance. |
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