Say you’re concerned that someone might steal your credentials or effect a payment by sneaking up on you and reading your implant.
How about including a latching reed switch inline with the antenna? Present a magnet’s north pole to connect the antenna to the chip and enable it, present the south pole to disconnect the antenna and disable the chip. Those with xG3 v1 implants would even carry the control magnet permanently on their person (or inside, rather)
The reed switch would be small enough to fit on top of even a wedge / slim / small flex implant, and would be soldered to the chip at one end, and soldered to the antenna at the other - the end of which would be shortened accordingly, but the capacitance would stay roughly the same as the length of “wire” within the reed switch itself would make up for the shorter coil.
As for solidity, smaller reed switches would be pretty stiff, even if they’re hollow. I tried breaking those things in the past and they’re pretty solid.
this sounds to me like a very interesting approach to affecting a power switch for a pegleg type device… like, zero power while off… that’s a huge difference compared to the hall effect sensor which must actively operate in low power mode even while “off”.
The problem with mechanical switches like a Reed switch is that they fail over time because of fatigue. They’re also not made for RF frequencies like 13.56MHz. The pressure connection between the contacts presents a high impedance to signals at that speed. It may impact communication.