https://thenextweb.com/gadgets/2018/07/04/it-sure-looks-like-the-galaxy-note-9-will-have-a-bluetooth-s-pen-but-why/

It looks like S Pen on Samsung’s Galaxy Note 9 is getting a big update: Bluetooth.

A filing with the FCC suggests the Note 9’s S-Pen will connect to the phone via Bluetooth LE. Previous devices used inductive styluses that didn’t require an internal battery, basically using a form of wireless power. But considering the S-Pen worked even when hovering above the screen, why would it need Bluetooth?