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NRF8001 antenna tuning

tilitililili

Hello!

I've developed a board with NRF8001 module mounted on it. Antenna on the board is much longer than in reference designs, so I can change the length. I also can add shunt capacitor/inductor. The problem is that I don't have a network analyzer. So is it real to tune the antenna without using special instruments?

  • 0 in reply to nick

    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

  • 0 in reply to nick

    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.

  • 0 in reply to nick

    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.

  • 0 in reply to nick

    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.

  • 0 in reply to nick

    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

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