Investigation On K/Ka-Band Orthogonal Linear Polarization Shared-Aperture Planar Array

As the demand for satellite communications continues to increase,multi-band,multi-functional,miniaturized and integrated antennas have grudually become the future trend.The shared-aperture antenna allows multiple antennas with different frequency bands and different functions to work independently in the same space through spatial layout and structural combination,and significantly reduce the size and weight of the system,so it has broad application prospects in satellite communication systems.Based on the substrate integrated waveguide technology(SIW)and stripline technology,this thesis explores the orthogonal linear polarization shared-aperture planar array operating in the K and Ka bands.The main work is as follows:Firstly,a broadband orthogonal coupling feed network applying to millimeter wave shared-aperture antenna feed network is proposed and designed by fusing the two structures of SIW and stripline.The network integrates a SIW coupler and a stripline coupler in the same space,effectively reducing the size by 36.4% compared with the structure formed by traditional stacked SIW couplers,and can achieve simultaneous orthogonal transmission of two sets of signals.The experimental results show that the structure can reach a bandwidth of 15.77%.The amplitudes and phases of the two outputs of each signal are stable,and the isolation of each group of signals exceeds 15 d B.This design has a good performance of transmission.Secondly,the K/Ka-band orthogonal linear polarization shared-aperture antenna for satellite communication applications is investigated and a new type of shared-aperture antenna unit is proposed and designed.The Ka-band horizontally polarized antenna is designed by using the SIW resonant cavity structure,and on this basis,the K-band vertically polarized antenna is designed by using the planar slot radiation structure.The simulation results show that the antenna unit can achieve-10 d B impedance bandwidths of 18.82-19.25 GHz and 28.58-31.06 GHz,3 d B gain bandwidths of 18.35-19.68 GHz and 27.84-31.56 GHz,and the port isolation of K and Ka bands exceeding 65 d B and 23 d B,respectively.Finally,the K/Ka-band orthogonal linear polarization shared-aperture planar array is studied.The feed networks of the corresponding band are designed hierarchically through the stripline technology,achieving port isolation higher than 44 d B.The proposed array antenna is processed by printed circuit board(PCB)technology,and the performance of the shared-aperture planar array is verified through measurement and error analysis.The measured results show that the antenna array has 3 d B gain bandwidths of 9.53%(18.18-20GHz)and 10.54%(28.4-31.56 GHz).