issue antenna

RE: issue antenna

MartinBL — Wed, 04 Oct 2017 10:45:32 GMT

Happy to help!

RE: issue antenna

omar — Wed, 04 Oct 2017 10:41:25 GMT

I will use your tips to optimize my circuit, Thank you so much Martin for your help,

Best regards,

Omar

RE: issue antenna

MartinBL — Wed, 04 Oct 2017 10:11:48 GMT

Please see my updated answer.

RE: issue antenna

omar — Mon, 02 Oct 2017 13:44:19 GMT

Thank you for your response Martin,

I changed again my pcb, I put the inductor next to C17, The line between the inductor and the PCB antenna is 50 Ohms impedance, I calculate this with a coplanar waveguide. I make the same antenna which is used in the PCA10040. And I added a capacitor footprint to adjust if it's necessary the antenna. The ground plane on the bottom layer, is it necessary for the matching circuit ? Do you think that it's better than the first PCB ?

Thank you for your response,

RE: issue antenna

MartinBL — Mon, 02 Oct 2017 09:48:01 GMT

You should always avoid long traces in high frequency antenna designs. Hence you should move the series inductor and "base" of the antenna closer to C17.
You cannot have too many via holes connecting the upper and lower ground layers around the matching network. You should place a few vias along the antenna and close to C17.
As for component values, you should start with what we suggest in our reference designs, then measure the performance, and then use that as a guideline to to find the optimal values from there on.

We always recommend following our reference schematic and layouts found here.

Here is another good PCB layout guideline.

Here you can also find the PCA10040 hardware files. Take a look and try to copy the matching network as well as the antenna.

EDIT: Continued:

Your changes look much better. Here are some more suggestions though:

In general you can't get too much grounding so try to clean up the traces a bit and pour some ground into the large empty spaces. Also try to use lots of vias on your entire PCB, not just around the antenna, to tie the top and bottom GND together. You should also have a large solid ground plane below the matching network.