Hi all, I’m looking for some expert guidance from anyone with deep antenna/reader tuning experience for the Apex Flex.
Goal:
I want to embed a 13.56 MHz NFC reader/writer inside a 2023 16-inch MacBook Pro, positioned on the left palm-rest area next to the trackpad, specifically to interface with my Apex Flex. I will be using it for APDU, NDEF, and GP command work, not just UID read.
Important notes / constraints:
-
I will be milling the aluminium chassis from the inside to reduce attenuation and create an RF “window” for the coil. I’m fine modifying the enclosure.
-
The reader must be fully internal and concealed — no external USB inserts, dongles, or visible modules.
-
Target coil placement will be directly under the palm-rest aluminium, with a thin ferrite sheet backing and a small milled cavity to improve coupling through the metal.
-
Coil must be thin and compact, ideally in the ~30×50 mm range, but I can adjust geometry if needed.
-
Must support ISO14443-A, full APDU exchange, and stable write power for the Apex Flex.
-
I am debating between a PN5180 front-end (for higher field strength and tuning flexibility) vs a compact PN532 module (space-saver, but lower power and less metal-tolerant).
-
A Proxmark3 is not an option for final install due to form factor — only for bench testing.
What I’m specifically asking the community:
-
Reader IC recommendation for best write reliability through a milled aluminium layer + ferrite (PN5180 vs PN532 vs other suggestions).
-
Antenna geometry guidance for a subdermal implant scenario at extremely close proximity (skin-to-coil through ~1–2 mm of aluminium, after milling).
-
Matching network considerations when the coil is this close to metal — e.g., expected detuning ranges or best-practice L/C starting points.
-
Whether anyone has real-world experience with Apex Flex write operations through ferrite + metal, and can comment on expected field strength losses.
I’m fully capable of custom PCB work, milling, and tuning — I just want to make smart design decisions before committing to a specific RF front-end and coil size. Any advice from those who’ve pushed NFC hardware to its limits (especially near metal or with implants) would be hugely appreciated.