Meandered trace antenna with nRF52832-QFAA

[MANGO]

Hi, I'm trying to create a custom PCB that uses nRF52832-QFAA and a Meandered trace antenna.

The PCB's environments are 4 layered, FR4, 1.6mm thick, and green PSR ink.

Thanks to Bjørn Spockeli's answer, I was looking at the dongle's schematic.

So my questions are,

0. When using the nRF52832, I don't need the parts in the red box (L1, L2, C3, C4, C5, L3 in the dongle's schematic)

and just replace the red part with the orange box part (L1 and C3 in PCA10040's schematic), right?

1. I believe the green part is the tuning parts. When using the nRF52832-QFAA,

should I use different values of RLC? Or should I follow the values in the green box?

-Best Regards

[bjorn-spockeli]

Hi Mango,

Q0: No, the nRF52832 has an On-chip balun so you do not need that many external components. As long as you follow the nRF52832 reference design( i.e. the orange box) you will be fine.

Q1: Yes, you will need to match the impedance of the antenna to 50 Ohms. This will depend on the PCB thickness, the size of the ground layers, vias, .... etc. Thus, there is no standard values that will work for every PCB, you usually have to find the correct value by trial and error. However, you can send the PCB to us and we will perform the tuning for you - free of charge. You will have to register for a Mypage account and then you can send the gerbers and schematics for review before you send the PCB.

Best regards

Bjørn

[MANGO]

Thanks, Bjørn.

This will depend on the PCB thickness, the size of the ground layers, vias, .... etc.

I'm a novice at PCB. As mentioned before, I'm thinking of a 4 layered, FR4, 1.6mm thick, and green PSR ink PCB.

I will place 4x4 vias at the ground pad of nRF52832-QFAA.

About the "etc", can you mention other parameters?

[bjorn-spockeli]

I would recommend going for a 2-layer design if possible. The factors that will affect the impedance of the antenna are: PCB thickness, the size of the ground layers, the distance between the internal layers, how well the ground layers are connected with vias and proximity to metal/housing of the PCB. I recommend that you read our Antenna Tuning white paper, found here.

[MANGO]

Then what thickness do you recommend when designing 2-layered FR4 PCB?

Back to the original question, when sending my custom PCB to you,

should I send a bare board(a board that has nothing soldered)?

Or should I assemble (mount at least nRF52832-QFAA) the parts before sending?

[bjorn-spockeli]

Our reference designs use a 1.6mm thick PCB. The board should be fully populated, expect for the tuning components. Our RF application engineers will provide you with instructions once you submit your schematics for review through Mypage.