Antenna matching components for NRF52832

[Saransh]

Hi,

I'm using the NRF52832 QFN (DCDC) for a PCB. Regarding the antenna matching components (C3,L1) it is recommended everywhere that one must use the exact same layout as given in reference PCB. However, the reference PCB layout works only for the dielectric material, thickness and board properties used in the reference board. For an arbitrary user specific board, one has to have the matching network (C3, L1 and the interconnecting microstrip lines) specific to that board. 

For that, what I did was: (1) Extracted the impedance seen looking from the ANT pin (30) into the matching network of the reference board PCB layout. I simulated the matching network as a combination of C3, L1, 50Ohm antenna load and all the interconnecting microstrip elements. This impedance is let say R+jX. (2) Then I simulated my own PCB's matching network and tried to tune its impedance to same as R+jX so that the source at ANT pin sees the same impedance as it would have for the reference board.

Doing so, I got a little different value of C3 and L1, which is what I would have expected anyway. The impedance plot from 2.4GHz to 2.5GHz looks more or less the same that I got for the reference board impedance simulation. However, I would like to show the layout and my simulation result to one of the antenna experts in Nordic itself so that I know if this is the right way to do it or I missed something. 

Please help as soon as possible, this is quite urgent for me.

Thanks a lot!

[ketiljo]

The matching network is transforming the impedance the nRF52 want to see to 50 ohm so it's easy to connect a 50 ohm load, an instrument or whatever. The area the two components occupies on the PCB is small so the influence of the PCB material will be negligible. The transmission line will be dependent on this, so here you have to design it according the PCB you're using. 

So make it easier for yourself by just using the values of C3 and L1 from the reference schematic. Note how C3 is grounded, this is far more important than the PCB material. 

You're welcome to share the layout of you want a review, either by making this case private or by opening a new, private, case.