K/Ka Band Shared-aperture Phased Array Antenna Loaded With Circular Polarizer

Satellite communication is widely used in various fields of modern society because of its characteristics of large coverage,long communication distance and anti-interference of ground environment.Antenna is an important part of communication system,and more and more attention has been paid to it.Modern communication systems tend to be more integrated,and antennas strive to achieve more complex functions in a limited area.How to realize circular polarization,multi-frequency and beam scanning in a limited area has become an issue in antenna research.The shared-aperture phased array antenna can significantly improve the aperture utilization ratio while having the scanning capability,and the polarization transformation can be realized by loading the polarizer.Through this way,The antenna can relieve the pressure of high density.This thesis do the research of the polarizer and phased array antenna used in K/Ka band satellite communication and the co-design methods.The K/Ka dual-band circularly polarized gate based on metal strip is researched.Firstly,a polarizer with different conversion characteristics in two bands is designed,and its working principle is analyzed through its cell topology and equivalent circuit model,and then the design and optimization are carried out based on the principle.Low insert loss and axis ratio performance are realized in both frequency bands.Then,a polarizer with different conversion characteristics in two bands is designed.its working principle is analyzed through its cell topology and equivalent circuit model.Using the transmission characteristics of the equivalent circuit model of two dimensions to work together to achieve the purpose of expanding the bandwidth.The problem of high density pattern layout is solved by miniaturization and de-symmetry of resonant structure.At last,a single layer structure is used to realize linearly-to-circularly conversion of two frequency bands with the same characteristics and a wide working band.The K/Ka dual-circularly polarized shared aperture phased array antenna loaded with polarizer is studied.Firstly,a dual-band linearly polarized phased array antenna with wide angle scanning capability is designed.It is combined with the polarizer to form the polarizer-air-antenna series microwave network.The transmission and reflection of different modes in the link are analyzed,and the whole combination is co-designed.The submatrix co-simulation method is used to verify and optimize.In addition,in order to expand the scanning range of the combination of antenna and polarizer,this work designed the polarizer element adapted to different angle incidence and do the partition combination.the partition scheme is optimized by algorithm according to the field distribution of the near field distribution.Finally,the combination of polarizer and linear polarization antenna array in K/Ka band is fabricated,and several groups of microstrip line feed nets are fabricated to test the performance under scanning condition.