Low-profile,Wideband And Wide Angle Scanning Phased Array Antenna

Since the early 1960s,phased array antennas have played an important role in radar systems with excellent performance in beam forming and steering.55 years later,phased array antennas are still under progress and have undergone a series of evolutionary processes.Today,phased array antennas are required to meet the radiation performance such as broadband and wide-angle scanning,under limitation of low profile,low cost and simple structure.Therefore,this paper has carried out in-depth research on the phased array antennas to achieve properties of low profile,wide-angle scanning,low design complexity and low cost.This thesis consists of the following parts:1.The relationship between the occurrence of grating lobes and the inter-element spacing during the array scanning with rectangular and triangular grid arrangements is studied.Since the array with triangular grid is better for large element spacing,a backed cavity with large element spacing was designed.After optimization of the antenna structure,the antenna can finally scan to±60°in the E-plane and±30°in the H-plane during the working bandwidth from 0.7f₀ to 1.16f₀.The antenna has low cross polarization level and the whole profile is as low as only 0.228?_H.Finally,a small-scale array of 2?3elements was processed and tested,and the test results were in good agreement with the simulation results.2.In order to design a low profile,broadband,wide-angle scanning phased array antenna,the common low-profile antenna elements are reviewed,e.g.,the unbalanced excitation antenna.To meet the requirements,in this thesis,the two dipole arms are designed to be asymmetric in order to achieve the balanced current on the two dipole arms and improve the impedance matching in the low frequency band.The results of the optimized antenna element in an infinite environment show that the antenna can scan to±60°in the E-plane and H-plane during the working bandwidth from 0.65f₀ to 1.2f₀.The final antenna element has a profile height of 0.2?_H.Finally,a full-wave simulation of12?12 elements phased array was performed.The simulation results meet the requirements of the index.Meanwhile,the radiation patterns of the antenna show that the antenna has good beam pointing ability,which proves the feasibility and stability of the design method.