Research And Design Of Microstrip Reflectarray Antenna

Reflectarray antenna become a research hotspot due to its features of small size, light weight, high gain and simple feed structure, etc. However, microstrip reflectarray antenna have a disadvantage of narrow bandwidth(about 10%), and meets many limitations in applications of large-capacity modern communication system. Therefore, how to expand the bandwidth becomes the research focal point of microstrip reflectarray antenna. Based on this background, this dissertation studies extensively on planar reflectarray antennas in published literatures and proposes two new broadband reflective element structures, for purpose of extending the bandwidth performance of reflectarray antenna. Infinite element analysis method is used to simulate and analyze the phase shift characteristics of the two new proposed element structures. Simulation results show that the range, sensitivity and linearity of the phase shift curves of the two new structures are much better than the published. Based on these two new proposed element structures, two reflectarray antennas are simulated, optimized, designed and tested. Simulated and tested results show that the relative operating bandwidth of these two array antennas raised to 17%, 20%, respectively.The main works conducted in this dissertation are as follows:1. Theoretical study of microstrip reflectarray antenna and simulation method of Waveguide Approach(WGA). Structures in published the literatures are modeled with WGA and analyzed comparatively, for purpose of mastering the simulation method.2. Study and analyze the factors which influence bandwidth of reflectarray antenna. Focus on the element structure’s phase shift characteristics, detailed analyses are conducted to find the key factors which affect the bandwidth. And therefore corresponding solution is outlined.3. Two new element structures are proposed and studied. It is shown that by increasing the resonant structure, new proposed element structures can optimized to extend bandwidth characteristic. Their phase-shift range, linearity, sensitivity are analyzed, simulated.4. Study and design of refectarray with use of the two new proposed element structures. The relectarrays are simulated, optimized, designed, fabricated and tested. The measure results show the relative bandwidth of the two new structural relectarrays raise to about 17% and 20%, repectively.The works carried out and new structures proposed in this dissertation have engineering reference value for reflectarray antennas applications.