NRF8001 antenna tuning

RE: NRF8001 antenna tuning

nick — Fri, 11 Mar 2016 18:54:02 GMT

Good luck with your project.

RE: NRF8001 antenna tuning

tilitililili — Fri, 11 Mar 2016 18:12:03 GMT

Nick, thank you very much for your advices!!!

I mounted 15 pf capacitors and it really helped! =)

RE: NRF8001 antenna tuning

nick — Fri, 04 Mar 2016 19:06:48 GMT

PCB Antenna's are a topic of its own so if you just random change the length or size, you will never now how its behave or how to tune it without specialist equipment. Change the caps so you can rule that out. remove the shunt. Then try to cut your antenna every time a little shorter en test again if it will function.

Some background information Antenna en tuning

RE: NRF8001 antenna tuning

tilitililili — Fri, 04 Mar 2016 18:31:15 GMT

I found nRFReady_Smart_Remote device (It operates at the same frequency) PCB layout. It contains PCB antenna, so I copied it from this project and made it much longer in order to have an opportunity ti change its length.

RE: NRF8001 antenna tuning

nick — Fri, 04 Mar 2016 18:19:05 GMT

If the capacitors of the crystal are wrong, the chip will not get the timing right. So i will give that the first try. Did you use a pcb antenna that is already used somewhere or did you designed your own antenna? because its actually pretty hard to design a good pcb antenna. In the reference design you won't see the actual antenna. It is just the trace to the antenna.

RE: NRF8001 antenna tuning

tilitililili — Fri, 04 Mar 2016 17:45:00 GMT

Thank you, I'll try to mount another capacitors for the crystal.

I have an adafruit breakout board with NRF8001 module and it works fine, when I connect it to the microcontroller unit. Shunt capacitor mounted on this board is 1.5 pF. I tryed to mount 1.5/1.2/1.8 pF on my board. And I also tryed to short the antenna without any shunt capacitor.

Yes, netc12_1 is my antenna. It's much longer than in reference designs.

RE: NRF8001 antenna tuning

nick — Fri, 04 Mar 2016 17:33:08 GMT

It is strange that you don't have any ble signal. Why did you use 12pf capacitors for your 16Mhz crystal instead of the 15pf in the reference design of nordic? I heard that the timing is very critical in order to get the bluetooth to function right.

Your layout looks good and seems to be almost the same as the reference board layout. Also did you added the shunt capacitor just on guess? maybe remove it en place the right capacitors for the crystal. is netc12_1 your pcb antenna or just the trace to your antenna?

Hope you get it to work properly

RE: NRF8001 antenna tuning

tilitililili — Fri, 04 Mar 2016 14:15:57 GMT

Hello!

RF part is a full copy from nRF8001-Reference Layout_Ver1_0.

RE: NRF8001 antenna tuning

FormerMember — Fri, 04 Mar 2016 09:35:24 GMT

If you don't have any range at all, it is possible that the layout is the problem. It is very important the RF part of the layout is a copy of our reference layout: It means that not only the component values should be the same as in our reference layout, but also the distance between the components and the geometry between the components.

RE: NRF8001 antenna tuning

tilitililili — Fri, 04 Mar 2016 08:41:07 GMT

Here are my schematic and PCB layout, If you need I can send full Altium projects.

drive.google.com/.../view

RE: NRF8001 antenna tuning

tilitililili — Thu, 03 Mar 2016 16:05:25 GMT

Thank you for your answer!

I tryed to make antenna as it is shown in reference design, but nothing changed, device didn't work...

Can you show a part of your schematic and pcb layout, please?

Thank you in advance.

RE: NRF8001 antenna tuning

nick — Wed, 02 Mar 2016 19:57:52 GMT

Hello

I just designed a board and chanced the reference design a little bit (different component layout with chip antenna). I got respectable range of 10 meter. I made the mistake to use 6mil trace instead of the suggest 8mil in the pcb reference design. So i hope my next board will be better.

Try to keep you're design as close as possible to the reference layout and you will do fine without network analyzer if you are happy with a near perfect range (just for hobby).

Calculate you're trace impendance here: emclab.mst.edu/.../index.html

My Eagle files for my homemade PCB. The board is made of FR4 0.8mm thick NRF51822.rar. Maybe you can send your files if you would like some comment on your design. I also made a new design without my errors. So don't use the layout for your design.

Nick