基于异构法向模螺旋的超宽带圆极化端射天线阵列研究

在目标定位、探测、图像传输等应用中，发展具有超宽带、圆极化、高辐射效率的端射天线已成为迫切需求。目前超宽带圆极化端射天线的实现方法少，且已有结构尺寸大，其应用受限。法向模圆极化螺旋尺寸极小，具有作为超宽带圆极化端射阵列阵元的潜力；但极低的辐射电阻限制了其应用，该制约因素亟待得到解除。本项目拟对法向模圆极化螺旋及其超宽带圆极化端射阵列展开深入研究，包括：1）利用螺旋异构体提高法向模螺旋的辐射电阻并实现圆极化，以解除传统法向模圆极化螺旋辐射电阻低的限制，实现高效率圆极化法向模螺旋天线；2）基于阵列综合理论和有源单元方向图分析法，研究阵列的圆极化端射机理和馈电方式，实现超宽带单圆极化端射阵列；3）基于左、右旋圆极化子阵的交叉排布和小间距阵元下的同频去耦方法，实现紧凑型超宽带双圆极化端射阵列。该项目能为兼容多应用的超宽带单、双圆极化端射天线需求提供新的解决方案，对于推动无线通信的发展具有重要意义。

In the applications of the target positioning, detecting, image transmission, etc., it is very urgent to develop the ultra-wideband, circularly polarized, high-radiation efficient end-fire antennas. However, there are very few methods to achieve the ultra-wideband circularly polarized end-fire antennas, and the current designs are usually very large in size, which limits their real applications. The normal-mode circularly polarized helix possesses an extremely compact structure, which is very potential to be the array element for achieving the ultra-wideband circularly polarized end-fire array. Nevertheless, the limitation is that its radiation resistance is extremely small, and this restriction needs to be relieved urgently. This project is going to conduct the thorough research on the circularly polarized normal-mode helix and its array for achieving the ultra-wideband circularly polarized end-fire characteristics. The contents of this project are as follows: 1) Employing the isomerically normal-mode helix to simultaneously maintain good circular polarization and enhance the radiation resistance, so as to overcome the limitation of the traditional circularly polarized normal-mode helix that suffers from low radiation resistance, and realize the high efficient, circularly polarized, normal-mode helix antenna; 2) Researching on the operating principle of the circularly polarized end-fire isomerically normal-mode helix array and its feeding technique based on the array synthesis and active element radiation pattern, so as to achieve ultra-wideband circularly polarized end-fire array; 3) Investigating on the cross-arrangement of the left- and right- handed circularly polarized sub-array and the decoupling method of the small spaced sub-array, and eventually realizing the compact, ultra-wideband, dual-circularly polarized end-fire array. This project can provide a new method for developing the ultra-wideband, single- and dual- circularly polarized, end-fire antennas that are essential for the multi-system applications, which is significant for the development of the wireless communication systems.