Design And Study Of Planar Reflectarray Antenna

With the rapid development of modern satellite communications and microwave communications,the role of reflectarray antennas is becoming more and more important.However,the traditional reflectarray antenna has defects such as bulky structure and bulkiness,which results in low flexibility of the communication system.In order to avoid this defect of the reflectarray antenna,a new type of "reflectarray antenna" concept is proposed.As the name suggests,this antenna brings together the advantages of reflectarray antennas and microstrip array antennas,and consists of many passive resonant units with similar structures and a feed.This kind of reflectarray antenna adopts the way of spatial feeding,and there is no need to design the complicated feeding network in the microstrip array antenna.With the development of microstrip printing technology and people's increasing requirements for low cost and high gain of antennas,this new type of reflectarray antenna has received increasing attention.This thesis has done an in-depth study on the planar reflectarray antenna.Based on the systematic summary of previous research results,two planar reflectarray antennas have been designed.The specific work content is as follows:1.Design and research broadband reflectarray antennas.A new type of linear polarization broadband reflection unit is designed.By optimizing the structural parameters of the unit,a reflection phase shift curve with better flatness is obtained.Then,a single-layered planar reflectarray antenna was designed using the designed reflector unit.The test results show that the antenna achieves a gain bandwidth of 19.5% of 1.5d B under the premise of ensuring other performance.2.Design and research the dual-band reflectarray antenna.First,two new types of single-layer reflective units with similar structures and different sizes are designed.The unit is to etch a U-shaped groove on a rectangular patch,and a better phase shift curve can be obtained by adjusting the size of the U-shaped groove.Analyzing the simulation results,it can be found that the mutual influence between the high and low frequency units is very small.Then,these two units are applied to the design of the dual-frequency linear polarization planar reflectarray antenna.The test results show that the antenna achieves a 17.5% gain bandwidth of 1.5d B in the first frequency band under the premise of ensuring other performance.A 1.5d B gain bandwidth of 8.4% is achieved in the second frequency band.