复杂扰动体域网中柔性天线不确定性的统计量化研究

Wearable flexible antennas exhibit significant fluctuation characteristics due to the interference of multi-source randomness in their immediate proximity environment, and this has a serious impact on the real-time communication quality of the wireless body area network (WBAN). In recent years, many mathematical models have been proposed to characterize the statistical distribution of some of the antenna key performance indicators, such as gain, bandwidth, resonant frequency, etc., in terms of input randomness. However, quantitative studies on the stochastic characteristics of antenna’s complete far-field radiation are still relatively rare. The applicant's previous research found that combining the parsimonious expression of the far-field radiation and the extraction of explicit statistical models is an effective way to solve this problem. This project aims to quantify the stochastic characteristics of the complete electric field in the far-field of WBAN flexible antennas in their continuous operating frequency band through statistical modeling. The model is designed to separate the impedance mismatch information contained in the electric field to enhance the robustness of the model to frequency shift effect. By introducing adaptive-learning based experimental design, we can improve the convergence rate of the model in case of high-dimensional input variable space. The modeling method is generally applicable to complex flexible antenna systems with large number of input variables, complex random distribution, strong coupling, and significant frequency shift effect. The constructed antenna model can be used to improve the accuracy of radio link analysis, as well as assist in the design & optimization of multi-parameter antennas.

可穿戴柔性天线因受紧邻环境中多源随机因素的干扰，其辐射性能呈现出显著的波动特性，这对无线体域网（WBAN）的实时通信质量造成严重影响。近年来，众多数学模型被提出用来表征天线的某些关键性能指标，如增益、带宽、谐振频率等在随机干扰下的动态分布。然而，对天线完备远场辐射的波动特性的量化研究仍较为少见。申请人前期研究发现，结合远场辐射极简表达和构建显式统计模型是一种解决该问题的有效路线。本项目拟通过建模对WBAN柔性天线在连续工作频段内的完备远场电场矢量的波动特性进行量化研究。通过分离远场电场矢量中所包含的阻抗不匹配信息单独建模，来增强模型对频率漂移的鲁棒性；通过引入自适应学习的实验设计，来提高模型在高维变量空间的收敛速率。该建模方法普遍适用于具有变量源多、随机分布复杂且耦合性强、频漂现象显著等特点的复杂柔性天线系统。所建立的天线统计模型可以提高链路分析的精确度，也可辅助多参变量天线的设计优化。

柔性天线被日益广泛地应用在无线体域网络（WBAN）中。部署在人体附近的柔性天线特别容易发生形变和受到外部环境干扰，其辐射性能也因而呈现出复杂随机的波动特性，对无线通信链路的稳定性和可靠性产生严重干扰。构建可以快速、准确地预测天线辐射性能的天线替代模型在MIMO天线系统、波束赋形技术、以及“天线-信道”联合仿真等方面都有着迫切的应用需求。.本项目提出了适用于复杂扰动WBAN环境下的柔性天线统计建模方法，对天线在连续工作频段内的完备远场电场矢量的波动特性进行量化研究。研究内容有四项：1）天线远场FF电场矢量频漂鲁棒性处理；2）可穿戴柔性全织物天线设计，及紧邻环境中随机干扰因素的标定；3）天线快速替代模型在天线优化设计中的应用；4）构建基于终端天线预测模型和传播信道预测模型相结合的“端到端”链路分析模型。.首先，提出了基于最小角度回归求解的混沌多项式展开方法对天线完备远场电场矢量进行精确建模；针对多尺度波动问题，提出了将大尺度和中小尺度波动分离开分别建模的思路，有效提高了天线模型的频漂鲁棒性和收敛速率。在满足相同建模精度的前提下可以将建模成本降低不少于50%。其次，基于腔模理论对圆形贴片天线的辐射模式进行分析，采用恰当的开槽技术激励起贴片天线的高次模，实现多频设计；采用多枝节法实现连续的谐振频点，叠加形成具有超宽带性能的紧凑型辐射贴片。所设计的全织物平面天线具有轻薄、柔韧、低剖面、易共型等特点，适用于健康监测、智能家居、应急救援等典型的WBAN应用场景。再次，将高效天线替代模型应用于超宽带平面天线的优化设计中，实现了辅助拓展其阻抗带宽或小型化设计的功能。最后，将终端天线远场电场矢量模型和三维传播信道模型相结合，构建“端到端”的通信链路模型，开展整体不确定性分析，为体域网网络规划和天线布局提供有价值的参考。