topic PN5180 Antenna Matching in NFC

PN5180 Antenna Matching

Draxter — Sun, 11 Apr 2021 14:56:42 GMT

Hello,

I try design PCB Antenna for the PN5180 but i have not a lot of experiences with RF circuits. I watched and read tutorials how to design NFC Antenna. I don't know if the antenna is properly designed for the PN5180.

I used NXP NFC Antenna Tool to design circuit. The app gave me a below results:

After That I assembled circuit and measure. My antenna has 3-turns. I used NanoVNA V2 for measured antena coil. Results:

La = ~1.48uH @13.56MHz,

Ra = ~2.5R @13.56MHz,

Ca = ~1 - 2pF (?)

I used RFSim99 tool for tuned antenna. After tuned the curcuit looks like this:

The NanoVNA shows:

Return Loss: -15.66dB
SWR: 1.45
Reflection power: ~2.7%
Z = 36.4R @13.56MHz

Is the antenna matching result good for PN5180?

Re: PN5180 Antenna Matching

fangfang — Tue, 13 Apr 2021 02:07:23 GMT

Hello,

The matching seems no problem. But One may refer to the video testing it.

URL: https://www.nxp.com/video/nfc-antenna-design-5-test-qualification:ANTENNA-TEST-QUALIFICATION-VIDEO.

Hope it help you. Have a nice day.

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Re: PN5180 Antenna Matching

Draxter — Tue, 13 Apr 2021 08:32:15 GMT

Thank you for the reply and advice.

Re: PN5180 Antenna Matching

Draxter — Tue, 10 Aug 2021 06:41:53 GMT

The circuit works but the maximum distance is only about 2-3cm. How Can I increase distance up to 7-8cm?

Re: PN5180 Antenna Matching

gabrielcuellar — Thu, 18 Aug 2022 17:44:51 GMT

Hi Draxter, you should use NXP-NFC-Reader Antenna Tuning.xls.

Must achieve measurement for PN5180
Z = 20R @13.56MHz for best transfer.

1- Measure your antenna with NanoVNA without circuit only antenna (Be careful with the calibration with the wire to measure), and obtain the R and L parameters (C not yet)

2-In these values in the NXP-NFC-Reader Antenna Tuning.xls (Attention in this) must reach the value indicated in the "C0 Calculated" field is very important.

3- Assemble your circuit and measure with the NanoVNA, then adjust the R L C values of the antenna in the simulation until you get a shape and values similar to those you read in reality.

4- You must in these values obtained from this "antenna" in the file NXP-NFC-Reader Antenna Tuning.xls and recalculate.

5- At this point you should have the final values to match at Z = 20 ohm 13.56Mhz

If step 5 didn't work for you, there may be something wrong, like a bad calibration or some value in the file that wasn't loaded correctly.

You should get this graph in the simulation and in reality

Example in my case

Note: Unconnect the soldering iron for add a change in your board if you have the nanovna connected.

Hope it help you. Have a nice day.