nice
there you go… soulder the antenna to the pads
cool.
My intention was to find out if anyone had done this. Because I’m not sure how I can do this.
Hi there,
Check out the Nordic website docs for the Resistors R’s (x2) you need to match the (Z)impendence of the antenna, others have done it. Basically you measure the resistance of the antenna and match it with a value of resistor. Look at the Data sheet for the equation.
HTH
GL 
PJ
The one you linked to in the first post, with caveats’ , C’mon man LOL…The other antennas will NOT work. 
FWIW you need to have an antenna compatible with the frequency and bandwidth for the spectrum you are operating in. Otherwise one could just use a coat-hanger 
The NFC-Antenna-p-1805 has a U.FL connector, but seeed xiao nRF52840 hasn’t U.FL receptor.
Should I remove the connector and then solder? If I’m correct how can I do this?
yes… or you could unsoulder from the antenna side and connect wires there
Yes, as he said…or get these, and make a pigtail…
U.FL Connector 5 Pack — RaceDayQuads $5.
HTH
GL PJ
2 Likes
yes what he said… lol
FYI, I’ve just soldered the peripherals.
However, it seems the mde card is not functional yet, I cannot read the NFC tag on my cell phone.
Regards,
WOW thanks for the update!
Hi there,
Yea, That’s NEVER gonna work that way.!
Unfortunately it’s NOT a Plug and Pray connection, You 
got MORE work to do , LOL
see this from the Nordic Sheet, and others have had success with:
NFC uses two pins, L24 (NFC1) and J24 (NFC2), to connect the antenna. These pins are shared with GPIOs (P0.09 and P0.10) and the PROTECT field in the NFCPINS register in UICR defines the usage of these pins and their protection level against abnormal voltages. The content of the NFCPINS register is reloaded at every reset.
Note: The NFC pins are enabled by default.
NFC can be disabled and GPIOs enabled by defining the CONFIG_NFCT_PINS_AS_GPIOS variable in the project settings. The way of doing this depends on the Integrated Development Environment (IDE)/toolchain in use:
When using SEGGER Embedded Studio, select Project > Edit Options > Code > Preprocessor > Preprocessor Definitions and add the CONFIG_NFCT_PINS_AS_GPIOS variable.
When using Keil, go to Project > Options for Target > C/C++ > Preprocessor Symbols > Define and add the CONFIG_NFCT_PINS_AS_GPIOS variable.
Pins L24 and J24 are by default configured to use the NFC antenna, but if they are needed as normal GPIOs, R44 and R46 must be NC and R43 and R45 must be shorted by 0R.
see Figure Two.
It would be wise to read the data-sheet and some of the other posts on how to implement it correctly.
HTH
GL PJ
I have the Nordic , Dev board it comes with an NFC antenna, I’ll measure the Z and get back.
as a point of reference , what is the (r) of your antenna?
https://infocenter.nordicsemi.com/index.jsp?topic=%2Fnwp_026%2FWP%2Fnwp_026%2FnWP_026_NFC_antenna.html
why would they make an antenna that needs extra stuff added to make it work… what da?
1 Like
Indeed!
Doesn’t make sense. The antenna should fix these extras.
Hi there,
IDunno, The LIB was broken a while back, But some others have posted they got it to work
No clear Solution on it yet other than Nordic’s Dev brd.
HTH
GL PJ
No problem… 
Hi there,
Yea , those are cool, two way comms. But the Seeed Xiao Nrf52840 only act as a (NFC TAG) you get a reader near it, and it spits out , a www, or Ascii string, or WIFI credz, Which was the main purpose along with www’s NO receive data possible. (it can’t read a TAG) 
The antenna allows it to answer.
HTH
GL PJ
we need a wow icon to click on… cause sometimes a post just doesnt rise to the level of love…
1 Like
Since this topic is still recent, for those interested:
I managed to replicate Arduino Code on the Wiki using the “Seeed nRF52 mbed-enabled Boards Library” as stated and both antennas described in there (NFC Usage for both versions | Seeed Studio Wiki)
1 Like
Hi there,
Looks Good , Start a new topic. It will be better.
the caps seem to make a fair bit of difference for the distance you get. Even the small antenna goes good with the right values…
GL PJ