NRF52832 WLCSP ANT pin impedance

RE: NRF52832 WLCSP ANT pin impedance

Kaja — Thu, 16 May 2019 09:20:02 GMT

Hi,

we have not measured the exact impedance, but as I said it should around 80 Ohm, and that is what you are seeing.
This is the impedance you should be seeing when both the radio and antenna is matched to 50 Ohm.

Best regards,
Kaja

RE: NRF52832 WLCSP ANT pin impedance

madroche — Wed, 15 May 2019 17:59:17 GMT

Working backwards from the L network (3.3nH series and 1pF shunt to the the source) I am seeing the impedance as 80 - j44 ohms. Can you confirm this value is accurate with someone? Thank you

RE: NRF52832 WLCSP ANT pin impedance

Kaja — Wed, 15 May 2019 05:59:50 GMT

Hi again,

I don't know the exact impedance, but it's around 80 Ohm. --> The matching components transforms it to 50 Ohm.

Best regards,
Kaja

RE: NRF52832 WLCSP ANT pin impedance

madroche — Tue, 14 May 2019 21:11:49 GMT

Ok thank you! Do you know the S11 impedance of the pin itself? Without the recommended LC filter? Please let me know, thank you.

RE: NRF52832 WLCSP ANT pin impedance

Kaja — Tue, 14 May 2019 06:59:46 GMT

Hi Madeleine,

[quote user=""] Does the recommended 1pF shunt and 3.3nH series transform the pin impedance to 50 ohms?[/quote]

- Yes they do.

You can always simulate, but the components values needs to be tuned on the on the actual PCB. For the matching network for the radio this tuning is based on the actual RF emissions, not the impedance, to control the harmonics and output power. When you do this, you indirectly get the right impedance.

For matching the antenna, you should put in a matching network, like a Pi or T, and the transmission line between the matching networks should be 50 Ohm. - Here you tune based on the impedance.

Best regards,
Kaja