Analysis,Design And Application Of Circular Polarization Selective Surface

Circular Polarization Selection Surface(CPSS),as a spatial filter,is widely used in the design of Polarization diversity antenna systems because of its selectivity for different circularly polarized electromagnetic waves operating at the same frequency.Due to the disadvantages of the traditional CPSS unit,such as complex processing and unstable oblique incident performance,it is difficult to apply it to the design of multifunctional antennas in communication system.Therefore,the exploration of simple CPSS structure and its application in antenna design has a certain research value.In this thesis,the bending coupling line is used to realize the miniaturization of CPSS unit and simplify the difficulty of processing and assembly,and a method to improve the axial ratio is also presented.On this basis,a new CPSS unit is used to realize the design of multifunctional circularly polarized reflectarray antenna.The specific research contents are as follows:(1)Firstly,the research background and significance of CPSS are introduced,then classifies and compares the traditional CPSS from the basic working principle,and focuses on analyzing the CPSS based on Pierrot element.Finally,a series of detailed design procedures are given for the design of the reflectarray antenna,which lays a foundation for the subsequent design of circularly polarized reflectarray antenna using CPSS element.(2)Based on the principle of the Pierrot unit,a new type of miniaturized CPSS with low axial ratio is designed.The resonant current on the surface of the unit is analyzed deeply and the radiation model of the surface current is established.According to the current radiation model,the zero-point frequency of cross-polarization of CPSS was calculated,and the relationship between the unit size and the resonant frequency was fitted by polynomial function,so that the rapid design of CPSS was realized.Finally,the crosspolarization of CPSS is analyzed,and a design method which can improve the axial ratio is proposed.(3)Single-layer Printed Circuit Board(PCB)technology was used to process the new CPSS structure,and the linear polarization space test system was used to measure it,then the final measurement data of the CPSS structure was obtained.The measured results of the new CPSS structure and its improved structure with low axial ratio are in good agreement with the full-wave simulation results,and the oblique incident performance is stable.(4)The multifunctional reflectarray antenna is designed by using a new CPSS element,which realizes the function of beam shaping the left-handed circularly polarized incident wave and transmitting the right-handed circularly polarized wave at the same frequency near 10 GHz.A fast calculation program for radiation pattern was written based on array theory,and its reliability was verified by full-wave simulation software.Finally,the multifunctional reflectarray antenna was fabricated and measured.The gain at 10 GHz was 21.4d B,the aperture efficiency was 35.5%,and the axial ratio was less than 1.6d B.The transmission performance of the multifunctional reflectarray antenna was verified.