| Miniaturization,multi-functional,high-density integration has become typical features of the modern communication technology.As an important part of communication system,antennas also face some challenges,such as miniaturization,multifunction,high-density integration and so on.The shared-aperture antenna aims to place multiple antennas in the same radiation aperture plane,and so as to reduce the area occupied by the antenna greatly.At the same time,antennas also need a lower profile to realize the miniaturization of the whole system.Based on the different application background,this paper studies the shared-aperture antenna.The research is divided into the following three aspects:1)Aiming at the sub-6G and mmwave bands of the future 5G communication system,a miniaturized 3.5GHz/38GHz shared-aperture antenna array with high frequency ratio,high isolation and high aperture utilization is proposed.In the aspect of radiator design,in order to achieve the high aperture reuse ratio,mmwave band substrate integrated back cavity slot array antenna is fully reused as sub-6G miniaturized shorted patch antenna,and the closed substrate integrated cavity structure can effectively isolate the coupling between the two frequency bands.In the aspect of feeding structure design,the shorted structure of the sub-6G miniature shorted patch antenna is reused as the feed structure of the mmwave band antenna.This structure reuse not only improve the aperture reuse ratio but also inprove the the isolation between the two bands antenna.The experimental results show that the antenna can effectively reduce the occupied area by more than 75%,and achieve the isolation of more than 70dB（@sub-6G band）and 40dB（@mmwave band）.This shared-aperture antenna can effectively support the sub-6G and mmwave frequency band anennas working at the same time in the future 5G applications.2)Aiming at the military application of the frequency hopping anti-jamming radar,an ultra-low profile S/X dual-band shared-aperture phased array antenna with medium frequency ratio,two-dimensional large beam scanning coverage and the same linear polarization is proposed.In the aspect of array topology design,triangle array of S-band elements and square grid array of the X-band element are adopted.It can achcieve the array spacing of the two bands antennas around half of the wavelength,so the dual frequency can realize two-dimensional large beam scanning coverage.In the aspect of radiator design,in order to achieve ultra-low profile performance,the X-band patch antenna is reused as the S-band mushroom shaped radiation structure.Due to the structure reuse technology,the overall profile of the antenna is less than 0.04λ0（λ0 is the wavelength in the free space at the central frequency of the S-band）.Finally,the antenna prototype as processed based on the printed circuit board（PCB）technology.The measured results show that the S/X band antenna can achieve a wide beam scanning range of±50°with a maximum gain drop of 5dB.3)Aiming at the millimeter wave high-throughput satellite communication system,a K/Ka dual-band dual-circularly polarizated shared-aperture phased array antenna with small frequency ratio,high isolation and two-dimensional widebeam scanning coverage is proposed.In the aspect of array topology design,two different topologies for the dual-band antennas are optimized to form a hybrid topology so as to realize the arrangement close to half of the wavelength of two the band antennas.In the aspect of radiator design,based on the integrated back cavity patch antenna,through hollowing out the weak electric field area of low-frequency patch antenna,and replacing it with high-frequency patch antenna,the high-density array of dual frequency radiator is realized.Furthermore,based on the principle of multi-structure and multi-mode decoupling,the dual frequency patch radiators in the high-density array can work normally without mutual interference.In the aspect of array antenna design,the axial ratio performance of array antenna is improved and the axial ratio bandwidth of array antenna is expanded by rotating feed configuration.The simulation results show that the channel isolation between the two band antennas is greater than 30dB（@20GHz）and20dB（@30GHz）.At the same time,K/Ka band antenna can achieve a wide beam scanning range of±50°and an absolute working bandwidth wider than 1GHz. |
