NFC Antenna Design Help!
Hello Im currently working on a uni project and i kind of need some help,
Im currently working on a small passive NFC prototype using a NXP NHS3152. The goal of the project is to keep the PCB as small and discreet as possible and only bieng powered only from a phone NFC field with the MCU taking a couple of low-power analog readings and sending a simple result back to the phone.
I would like some help with the power side before I go too far with the antenna and PCB layout.
The system would ideally run around 1.8 to 2.0 V when powered by the phone. The sensing load is expected to be fairly low, roughly in the range of a few µA up to maybe 60 to 70 µA depending on the resistor values used.
Rough power estimate would be at 1.8V, 5 µA = about 9 µW, 20 µA = about 36 µW, 65 µA = about 117 µW
and for 2V its would be, 5 µA = about 10 µW, 20 µA = about 40 µW, 65 µA = about 130 µW
I would only power the analog measurement section for less than a second so the average current should be lower than the active measurement current.
Main questions:
- Is this kind of power budget realistic for a passive NFC tag powered by a smartphone?
- For the NXP NHS3152, what is the best practical NFC antenna approach on a small custom PCB or if anyone has a NFC design for these specifications?
I’m not trying to transfer much data, just wake from the phone field, take simple readings, and send a small result back to the phone.
Any advice from people who have worked with passive NFC sensor tags, NHS3152/NTAG-style parts, or small NFC antennas would be appreciated!!!
Edit: Forgot to mention the Maximum Size of the Antenna is around 5.8cm × 5.8cm and its going to be printed on a flexible substrate.