for nrf51822 , from where i can get the geometry, relative placement of the components with respect to each other, and the lengths of the transmission lines. only the values of the components are given in nrf51822 datasheet.

[Hamid@]

nrf

[bjorn-spockeli]

Hi Hamid, 

the reference design for the nRF51822 is used on the nRF51 DK and you can find the hardware layout files here: https://www.nordicsemi.com/-/media/Software-and-other-downloads/Dev-Kits/nRF51-DK/nRF51-DK---Hardware-files-1_2_0.zip. From these you should be able to see the relative placement as well as measure the length of the transmission lines

Best regards

Bjørn

[Hamid@]

Hi Bjon

first of all really thanks for you quick reply

i think my question was not clear i am only interested in antenna design for nrf51822 ,i follow this blog post ' General pcb design guidelines for nrf51' and its link is  "https://devzone.nordicsemi.com/nordic/nordic-blog/b/blog/posts/general-pcb-design-guidelines-for-nrf51" 

 actually i want to use a chip antenna and then will connect it with nrf51, as shown below.

my question is, is it fine to use two matching circuit one for the chip antena as suggested by manufacturer and one which nordic suggested as shown in fig. and will it work in this way.it is only for testing purpose.

my second question is  the chip antenna should be exactly 2.4 GHZ or if it is 2.45 GHZ does it matter.

[bjorn-spockeli]

Hamid@ said:

my question is, is it fine to use two matching circuit one for the chip antena as suggested by manufacturer and one which nordic suggested as shown in fig. and will it work in this way.it is only for testing purpose.

 The PI matching network in the nRF51 DK layout will be equivalent with the matching circuit from the antenna manufacturer. However, you will have to tune the matching circuit, i.e. adjust the values, so I recommend that you post your layout here on devzone for a review,

 

Hamid@ said:

my second question is  the chip antenna should be exactly 2.4 GHZ or if it is 2.45 GHZ does it matter.

 Any 2.4GHz chip antenna with 50 Ohm impedance should work.

[Hamid@]

thanks a lot , once i am done with my layout then i will upload it for reviewing.

regards 

Hamid

[bjorn-spockeli]

Great

[Hamid@]

Hi bjorn,

as you asked for reviewing my design when i am finished with it, so i am now done with it , so can you have a look for reviewing the matching circuit with antenna and the matching circuit with antenna on micro controller , so after connecting these two will it be fine. as shown below.

[bjorn-spockeli]

HI Hamid, can you provide the entire schematic in a pdf and the layout in Gerbers? I can make the case private if you like so that the shared files are only visible to you and me. 

Best regards

Bjørn

[Hamid@]

Hi bjorn

Thanks for your quick reply here are the files you asked for.

Kind regards

Nordic_.rar

[bjorn-spockeli]

HI Hamid, 

I have taken a look at your layout and these are my comments:

• The RF matching network is to far away from the nRF51822. You should move the matching comonents as close as possible to the nRF51822 and then use a 50Ohm transmission line from C6 to the antenna on the boards edge. I strongly recommend that you copy the nRF51822 reference layout, see attached PDF and schematic. 
• The same goes for the external crystals, they should be moved as close as possible to the nRF51822 as possible. The traces should be as short as possible.
• You do not have proper grounding. As you can see from the reference layout I attached, there should be plenty of vias that connect the top ground layer to the bottom ground layer. This is extremely important with regards to RF performance. 

nRF51x22-QFAx_Ref_Layout_v2.5.zip

Best regards

Bjørn