Numerical methods are important tools for design of modern antennas. Trust-region (TR) methods coupled with data-efficient surrogates based on finite differentiation (FD) represent a popular class of antenna design algorithms. However, TR performance is subject to FD setup, which is normally determined a priori based on rules-of-thumb. In this work, the effect of FD perturbations on the performance of TR-based design is evaluated on a case study basis concerning a total of 80 optimizations of a planar antenna structure. The obtained results demonstrate that, for the considered radiator, the performance of the final designs obtained using different FD setups may vary by as much as 18 dB (and by over 4 dB on average). At the same time, the a priori perturbations in a range between 1.5% and 3% (w.r.t. the initial design) seem to be suitable for maintaining (relatively) consistent and high-quality results.

翻译：数值方法是现代天线设计的重要工具。信赖域（TR）方法与基于有限差分（FD）的数据高效代理模型相结合，代表了一类常用的天线设计算法。然而，TR方法的性能受限于FD设置，而FD设置通常基于经验法则预先确定。本研究以平面天线结构为例，通过总计80次优化实验，评估了FD扰动对基于TR的设计性能的影响。所得结果表明，对于所考虑的辐射器，使用不同FD设置获得的最终设计性能差异最高可达18 dB（平均差异超过4 dB）。同时，在初始设计1.5%至3%范围内的先验扰动似乎有助于维持（相对）一致且高质量的结果。