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Why do simulated antenna efficiencies sometimes exceed unity, and how should this be diagnosed?

While simulating antennas in CST or HFSS, I occasionally see radiation efficiencies greater than 100%.
This seems physically impossible, and I want to identify whether it is a modeling error, normalization issue, or meshing artifact.
I need systematic approaches to diagnose and correct this problem.

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By Mayank Singh Answered 1 year ago

From my experience, simulated antenna efficiencies exceeding 100% usually result from modeling or post-processing errors, not physical reality. I have seen causes such as incorrect port definitions, improper power normalization, neglected lossy materials, or meshing artifacts. I would recommend checking that port excitations and reference impedances are correctly set, all conductive and dielectric losses are included, and the far-field integration is correctly normalized. In practice, refining the mesh and verifying results against analytical or measured benchmarks often resolves apparent over-efficiency, ensuring physically meaningful simulation outputs.

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