A Study On Planar And Conformal Ultra-wideband Phased Arrays Based On Enhanced Mutual Coupling

Phased array antennas play an extremely important role in wireless electronic communications,radar,and various types of electronic countermeasures.Their performance can directly affect the performance of the entire system.With the development of the antenna industry and the higher requirements imposed by the electronic system on the antennas,traditional narrow-band antennas can no longer meet their needs,thus phased arrays of broadband and even ultra-wideband come into being.In ultra-wideband phased arrays,ultra-wideband phased array antenna based on enhanced mutual coupling effect has become a research hotspot in the field of antennas due to their advantages such as low profile wide bandwidth and large scanning angle,etc.However,the studies on conformal phased arrays based on the enhanced mutual coupling effect are rarely seen.The conformal phased arrays based on tightly coupled dipoles have the features of low profile,easy to conform to the platform,wide-bandwidth and wide scanning angles and other characteristics,which are particularly important for some special platforms.This thesis,is started with a planar ultra-wideband array based on tightly coupled phased array,and then the conformal ultra-wideband phased array based on tight coupling is explored.A conformal ultra-wideband phased array with three octaves bandwidth and wide scanning angles is realized in the C-Ku band.The major content of the thesis is arranged as follows:Firstly,the research background and significance of this topic are elaborated.The development status of the tightly coupled phased planar array and the conformal array at home and abroad are summarized briefly.The basic principle of phased array antenna and the equivalent model of conformal array antenna based on tightly coupled dipole are also reviewed.Secondly,a cross-shaped symmetric dipole unit is designed to realize the C-Ku band dual-polarization scanning and the planar dipole elements is based on tightly coupled dipole.Below the upper coupling side,a metal patch is used for the auxiliary coupling to increase the antenna's operating bandwidth.For a better performance of impedance matching,metal matching layer technology is use with non-balanced feed.Thirdly,based on the above tightly coupled ultra-wideband planar array element,a novel tightly coupled ultra-wideband conformal array element is designed based on a cylindrical platform.The planar array antenna and conformal array antenna array are designed based on the element.Simulation results show that both the ultra-wideband planar array antenna and the ultra-wideband conformal array antenna based on tightly coupled dipoles are capable of obtaining good radiation effects and achieving the estimated wide-bandwidth and wide scanning angle.Finally,an ultra-wideband conformal phased array antenna based on the tightly coupled dipoles with 2D scanning ability is fabricated and measured.Experimental results and simulation results are in reasonable agreement,thus verifying the correctness of the designed ultra-wideband conformal phased array based on tightly coupled dipoles.