Koziel Slawomir, Pietrenko-Dabrowska Anna
School of Science and Engineering, Reykjavik University, 101 Reykjavik, Iceland.
Faculty of Electronics, Telecommunications and Informatics, Gdansk University of Technology, 80-233 Gdansk, Poland.
Sensors (Basel). 2019 Apr 15;19(8):1806. doi: 10.3390/s19081806.
Design of antennas for the Internet of Things (IoT) applications requires taking into account several performance figures, both electrical (e.g., impedance matching) and field (gain, radiation pattern), but also physical constraints, primarily concerning size limitation. Fulfillment of stringent specifications necessitates the development of topologically complex structures described by a large number of geometry parameters that need tuning. Conventional optimization procedures are typically too expensive when the antenna is evaluated using high-fidelity electromagnetic (EM) analysis, otherwise required to ensure accuracy. This paper proposes a novel surrogate-assisted optimization algorithm for computationally efficient design optimization of antenna structures. In the paper, the optimization of antenna input characteristic is presented, specifically, minimization of the antenna reflection coefficient in a given bandwidth. Our methodology involves variable-fidelity EM simulations as well as a dedicated procedure to reduce the cost of estimating the antenna response gradients. The latter is based on monitoring the variations of the antenna response sensitivities along the optimization path. The procedure suppresses the finite-differentiation-based sensitivity updates for variables that exhibit stable gradient behavior. The proposed algorithm is validated using three compact wideband antennas and demonstrated to outperform both the conventional trust region algorithm and the pattern search procedure, as well as surrogate-based procedures while retaining acceptable design quality.
物联网（IoT）应用中的天线设计需要考虑多个性能指标，包括电气性能指标（如阻抗匹配）和场性能指标（增益、辐射方向图），同时还要考虑物理限制，主要是尺寸限制。要满足严格的规格要求，就需要开发由大量需要调整的几何参数描述的拓扑复杂结构。当使用高保真电磁（EM）分析评估天线时，传统的优化程序通常成本过高，而高保真电磁分析是确保准确性所必需的。本文提出了一种新颖的代理辅助优化算法，用于天线结构的高效计算设计优化。本文介绍了天线输入特性的优化，具体而言，是在给定带宽内最小化天线反射系数。我们的方法涉及可变保真度的电磁模拟以及一种专门的程序，以降低估计天线响应梯度的成本。后者基于监测天线响应灵敏度沿优化路径的变化。该程序抑制了对表现出稳定梯度行为的变量基于有限差分的灵敏度更新。所提出的算法通过三种紧凑型宽带天线进行了验证，并证明在保持可接受的设计质量的同时，优于传统的信赖域算法、模式搜索程序以及基于代理的程序。
