When the first commercial electromagnetic (EM) simulators appeared in the late 1980s and early 1990s, we were thrilled to be able to accurately simulate a single microstrip discontinuity, even if the simulation ran overnight. Today, computer hardware is cheaper and much faster, and EM simulation software is more efficient and sophisticated. Even so, putting an EM simulator inside an optimization loop is still not practical in most cases. Even our simple N = 5 hairpin filter example does not lend itself to directly driven EM optimization. The desire to efficiently optimize microwave filters using accurate EM simulation data led us to the port-tuning concept [1].

中文翻译：

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微带折叠发夹滤波器的端口调谐 [应用说明]

 当第一个商用电磁 (EM) 模拟器出现在 1980 年代末和 1990 年代初时，我们很高兴能够准确地模拟单个微带不连续性，即使模拟运行了一夜。今天，计算机硬件更便宜、速度更快，而电磁仿真软件更高效、更复杂。即便如此，在大多数情况下，将 EM 模拟器置于优化循环中仍然不切实际。即使我们简单的 N = 5 发夹滤波器示例也不适合直接驱动的 EM 优化。使用准确的 EM 仿真数据有效优化微波滤波器的愿望使我们想到了端口调谐概念 [1]。