| With the growing demand for satellite communication technology and the continuous development of satellite communication technology,the performance requirements of antennas are getting higher and higher.Requirements such as broadband,circular polarization,and miniaturization have become hot topics of research.Since shared-aperture technology can effectively improve the aperture efficiency and the compactness of the antenna,and is easy to be integrated with communication systems,it is suitable for the demand of satellite communication antenna systems.This thesis aims to research millimeter wave shared-aperture antenna arrays from the demand of satellite communication antennas,and the work includes the following aspects:（1）Analysis and design of a K/Ka-band shared-aperture antenna unit.According to the design requirements,the array layout topology is analyzed,to ensure that the antenna array of two bands has the ability of large angle beam scanning,and the square layout topology is adopted.The K-band antenna and Ka-band antenna are nested and placed,to realize the half-wavelength array of two antennas.Firstly,the design of the Ka-band antenna unit is considered,and a slotted circular microstrip antenna loaded with a parasitic patch is designed to achieve a 10.8%axial ratio bandwidth and 17.5%impedance bandwidth with a single feed to achieve broadband circular polarization radiation in a small size,while the profile height is only 0.110λ.Then,a K-band antenna unit is designed,which achieves 12%impedance bandwidth with circular polarization radiation capability.Finally,the Ka-band antenna unit is placed in the center of the K-band antenna for co-simulation,and the results show that the impedance matching performance of the antenna is not affected,and the isolation is 21.25 dB for the K-band and 15.15 dB for the Ka-band.（2）Analysis and design of a K/Ka-band shared-aperture antenna array.Firstly,a coaxial-fed K/Ka-band shared-aperture phased array antenna array is designed with a square arrangement topology.In terms of performance,both K and Ka-band antenna arrays can achieve 50°beam scanning,while the gain drop is less than 3 dB.During the scanning process,the two bands’antenna arrays achieve 10%and 12%impedance bandwidth,and 15%and 12%axial ratio bandwidth,respectively.Then four K/Ka-band shared-aperture antenna arrays with the addition of a feed network are designed to achieve beam scanning at K-0°,K-50°,Ka-0°,and Ka-50°,respectively.The results show that for the two antenna arrays with K-band 0°and 50°beam scanning,the impedance bandwidth is greater than 13.7%,the 3-dB axial ratio bandwidth is greater than 7.3%,with 5-dB axial ratio bandwidth greater than 11%,and the gain drop of 50°beam scanning less than 3.5 dB.For the two antenna arrays with Ka-band 0°and 50°scanning,the impedance bandwidth is greater than 17%,with 3-dB axial ratio bandwidth greater than 9.8%,and 5-dB axial ratio bandwidth greater than 13.9%.The proposed K/Ka-band shared-aperture antenna array can meet the requirements of the design specifications. |
