Research And Realization Of Ku-band Broadband Mobile Satellite Communication Antenna

With the development of wireless communication technology,higher requirements are put forward for the design of antenna in satellite communication system.The microstrip antenna has the advantages of thin profile,easy miniaturization,easy integration with active circuit,diversified feed and polarization forms,etc.It is widely used in various systems.In satellite communication system,the use of dual-polarization antenna can improve the utilization of communication frequency band,expand the communication capacity of the system,and also improve the space utilization of the antenna.The following tasks have been focused for the Ku-band dual-polarization microstrip antennas:In order to realize the Ku-band dual-polarization one-dimensional phase scanning antenna array,the 16×1 slot-coupled patch antenna array is designed.Firstly,the slot coupled patch antenna unit is designed,then the antenna elements are arranged symmetrically to form an one-dimensional array.The feed structure is divided into three sections.First,the suspended microstrip line divides the power into eight channels,which is vertical back to the antenna,and connects to the transition microstrip lines.Then,the transition microstrip lines are connected to the coaxial lines.Finally,the coaxial lines divide the power into two channels to the feeding microstrip lines of the antenna units.The vertical polarization ports are in same phase feed,and the horizontal polarization ports use the half-wavelength microstrip line to realize the reverse phase feed.The antenna array is miniaturized and can be composed of a one-dimensional phase sweep array.The use of the suspended microstrip line reduces the loss of the feed network.The measured results show that:in the 10.7 GHz-12.2GHz band,the S₁₁is lower than-6d B,the gain is higher than 9d Bi,and the cross polarization of the central frequency point is lower than-18.08d B.Then,in order to realize the Ku-band dual-polarization plate antenna array,a 16×16circular patch antenna array is designed and implemented.The antenna units use microwave foams as the medium support,and the radiation patch is a circular patch.The adjacent antenna units are staggered to form a two-dimensional array.The feed network adopts balanced feed mode.The two polarization-fed dielectric plates are placed in parallel on the back of the antenna,and form suspended microstrip line power distribution networks with the metal structure.Then the suspended microstrip lines are connected to the feeding copper columns as the top radiation patch feed.The two polarization-fed networks both use the half-wavelength suspended microstrip line to realize the reverse phase feed.The antenna array adopts symmetrical balanced feed mode,which improves the isolation of the antenna polarization port and improves the cross polarization.The impedance bandwidth of the antenna is widened by using circular patch and air foam.The layered placement of the feed network reduces the antenna profile and reduces the weight of the antenna.The use of the suspended microstrip line reduces the loss of the feed network.The measured results show that:in the 12.2GHz-14.5 GHz band,the S₁₁is lower than-10d B,the gain is higher than 27.17d Bi,and the cross polarization of the central frequency point is lower than-38.52d B.