Design Of Wideband And High Gain Printed Yagi Antennas

With the gradual improvement of the degree of social information and the increasingly scientific and intellectualized life,the application of wireless communication technology has spread around us.As a key part of the wireless communication system,the antenna has an important impact on the operation of the whole system.In recent years,the system has put forward higher and higher requirements on the structure and performance of the antenna.In particular,bandwidth,gain and direction have become the most important performance indicators for antennas.How to broaden the bandwidth and improve the gain has become a hot topic.In this paper,based on the study of broadening bands and increasing gain methods,the design of the monopole broadband printed Yagi antenna and broadband Quasi-Yagi antenna loaded with split-ring resonators.The main contents of this thesis are as follows:(1)The basic characteristic parameters of the antenna are introduced,such as the bandwidth,direction and gain of the antenna.Besides,the methods of broadening the bandwidth of the antenna and the way to improve the gain are also analyzed.(2)Through the research on the structure and radiation mechanism of printed Quasi-Yagi antenna,a monopole broadband printed Yagi antenna with endfire radiation performance is designed combining the reflection dipole loaded branch and rectangle director dipole.And the monopole antenna is used as the active oscillator of the Quasi-Yagi antenna.The result shows that the antenna can operate at 2.01-4.03 GHz and the relative impedance bandwidth is 66.9%.Besides,a stable gain of about 4.98-8.21 dBi is obtained.(3)In order to further improve the gain of the antenna,based on the broadband printed monopole Yagi antenna,a novel broadband Quasi-Yagi antenna is designed by loading two groups of split-ring resonator units into the front end of the director dipole.The-10db impedance bandwidth of the improved antenna is 2.01-4.04 GHz and the relative bandwidth is 67.1%,the maximum gain is 10.14dBi.Compared with the original antenna,the gain in the endfire direction is increased by 2dB on the basis of maintaining the bandwidth of the antenna.The radiation performance of the antenna enhanced.