Reading an HFSS Convergence Plot Honestly

The most dangerous output of an electromagnetic solver is a confident wrong answer, and the usual route to one is treating convergence as correctness.

What Delta-S actually tells you

Delta-S measures how much the S-parameters changed between successive adaptive passes. A small Delta-S says the *mesh* has stopped changing the answer. It says nothing about whether the model, the boundaries or the excitation represent the thing you meant to simulate.

Checks worth doing every time

- Does the result change if you enlarge the radiation boundary? - Does it change with a finer initial mesh? - Does a simple analytical case solved the same way give the textbook answer?

Placeholder article — illustrative until the HFSS series is published.