Practical RF · 10 min read
How to keep read range when your antenna has to sit on a battery, a PCB ground plane, or a metal case.
Put an NFC coil flat against metal and it largely stops working: the metal supports eddy currents that oppose your field, slashing inductance and Q and collapsing read range. Phones, wearables, payment terminals, and industrial tags all face this. The fix is a ferrite layer between coil and metal — but only if you choose and place it correctly.
The preview ends here; the full guide covers permeability selection, thickness, saturation, and the layout mistakes that quietly kill performance.
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