Found in 2 comments on Hacker News
madengr · 2020-03-14 · Original thread
Not much. The F-117 is stealth mostly due to shape. The B2 stealth is mostly due to materials and construction techniques. You can run optimization routines to reduce scattering, but it’s not going to be huge improvements

This is a good book that discusses several techniques:

madengr · 2019-11-20 · Original thread
This is a good, lite technical read for those interested in stealth.

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