Design Of Broadband Array Antenna Based On Strong Mutual Coupling Structure

In the era of rapid development of 5G communications and the national industrial Internet of things,people's data demand for military and civilian communications is increasing day by day.According to Shannon's sampling theorem,the wider the bandwidth,the greater the amount of information that can be carried.The importance of the antenna as the front end of the communication system is self-evident.Ultra-wideband array antennas are also widely used due to their high bandwidth,high speed,and high resolution in the field of communication and detection.However,traditional ultra-wideband array antennas are often bulky and expensive,which limits their further development.This thesis adopts a new international ultra-wideband array antenna design method,tightly coupled ultra-wideband array design theory,and makes innovative improvements on this basis.The main work of the thesis includes the following parts:1.Analyze and study the principle and equivalent circuit model of the tightly coupled array antenna.First,discuss the impact of the floor reflection on the antenna impedance and bandwidth,and then further discuss some innovative methods for improving the bandwidth of tightly coupled array antennas in the world.2.Based on the tightly coupled array design theory,a new type of strong mutual coupling array antenna design model is proposed and designed.At the same time,in order to further reduce the cross-sectional height of the antenna array,we integrated an open route without adding extra dielectric layers through clever structural design.This open route serves to remove the dielectric impedance matching layer,so that the profile height of the array antenna is a quarter wavelength lower than that of the array antenna of the same frequency band,realizing the low profile design of the array antenna.Finally,the classic hyperbolic microstrip balun is used for broadband impedance matching.Through simulation and physical testing,the array antenna achieves VSWR<2.2 in the3?10GHz = 0° frequency band,gain greater than 20 d Bi,and the doubling bandwidth of the array antenna reaches 3.3:1,and its pattern characteristics are good.3.Discussed and analyzed the scanning blind spots of the two-dimensional array antenna with strong mutual coupling.The type of scanning blind spots in the two-dimensional wireless large-area array is studied,and the reason for the blind spots in this design is determined through a simple and effective feeding method.It is proposed to change the common mode current by adding a metal short bar on the E surface.The electric field distribution effectively removes most of the scanning blind spots in the frequency band beyond the grating lobe frequency.The design solution results are verified by HFSS simulation.