宽带圆极化紧耦合阵的研究

Wideband tightly coupled arrays (TCA) have received considerable interests recently. TCAs can alleviate inductive loading introduced by the ground plane using capacitive coupling among neighboring elements, and thus achieve a multi-octave impedance bandwidth. However, most of the researches focus on the development of linearly or dual-linearly polarized TCAs and very few designs are able to improve the impedance bandwidth and axial ratio (AR) bandwidth of a CP array by means of the strong mutual coupling between the array elements. To solve this issue, this project aims to investigate the fundamental theory and key technologies of the wideband circularly polarized tightly coupled array (CP-TCA). The main research contents include investigating the radiated fields of TCAs based on balanced and unbalanced elements, generating wideband orthogonally polarized E-fields with uniform amplitude, acquiring the phase differences of two orthogonal E-fields which are limited by a target function of array AR, and designing the external and integrated phase-shift network. Through theoretical analysis, numerical simulation and experiments, it is feasible to implement a CP-TCA which has a multi-octave bandwidth. The research outcome of this project will be beneficial to ultra-wideband wireless communications, ultrahigh data-rate satellite communications, and ultra-wideband radar systems.

近年来，宽带紧耦合阵引起了学术界的广泛关注，其利用阵元间的容性耦合，抵消地板引入的感抗，可以实现多个倍频程的阻抗带宽。但现有的相关研究多集中于线极化或双线极化紧耦合阵，少有利用阵元间的互耦，提升圆极化阵列阻抗带宽与轴比带宽的设计。针对此问题，本项目拟对宽带圆极化紧耦合阵的关键理论与技术开展研究。主要研究内容包括：基于平衡和非平衡单元的紧耦合阵辐射电场数学模型的研究、幅度均衡的宽带正交电场的建立、基于轴比目标函数的正交电场相位差信息的获取、外置和集成宽带移相网络的设计等。通过理论分析、数值仿真与模型实验的方式，探索具有多个倍频程带宽的圆极化紧耦合阵的系统设计理论和设计方法。项目的成果预期会对超宽带无线系统、超高数据率卫星通信链路及超宽带雷达系统等产生重要的理论和应用价值。

本项目通过利用阵列单元间的强耦合，对宽带圆极化紧耦合天线阵的关键理论和技术开展研究，项目研究所产生的研究成果共发表SCI收录期刊论文9篇，其中包括5篇IEEE Transactions on Antennas and Propagation论文，1篇IEEE Transactions on Vehicular Technology论文，申请发明专利4项，成功授权2项。 具体取得的研究成果包括以下三个方面：在集成移相网络宽带圆极化紧耦合阵列的研究方面，实现了超过3:1阻抗带宽及2.3:1轴比带宽的圆极化紧耦合天线阵，该工作首次采用紧耦合的概念提升圆极化天线阵的带宽，并验证了宽带圆极化紧耦合阵的设计可行性与优秀的阵列性能；在非平衡圆极化紧耦合单元的研究方面，实现了17:1阻抗带宽及5:1轴比带宽的非平衡圆极化紧耦合单元，避免了紧耦合阵列设计中所需要的超宽带巴伦的使用，为实现基于非平衡单元的圆极化紧耦合阵提供了可能；在反射式圆极化紧耦合阵列的研究方面，利用单层平面天线口径实现了能覆盖10-30GHz频率范围的紧耦合反射阵列天线，该工作突破了传统反射阵列天线带宽无法达到多倍频程的局限，同时也避免了使用传统紧耦合阵列天线复杂的馈电网络，极大降低了紧耦合阵列的设计、加工复杂度。此外，本项目研究过程中，共培养与联合培养硕士研究生5名，已毕业硕士均进入华为、中兴等单位从事天线类的研发工作，为相关企业提供了一定的技术人才。整体而言，通过三年的持续研究，项目组圆满完成了研究计划。