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Layout review of Meandering Antenna

mpkasp

image descriptionHi -

Looking for a layout review of the NRF51822 antenna and oscillator design attached. The two main questions are:

  1. Is it recommended to remove the copper ground fill from around the antenna components? If so how much should be backed off?

  2. Does the design of the 16MHz oscillator traces look short enough?

  • +1

    Hi,

    The nRF51 dongle uses a meander antenna, it's reference design files can be found here. The reference designs are good, so they should be followed when possible. I'd also recommend reading this blog post on General PCB design guidelines for nRF51.

    As for your questions:

    • Yes, ground plane should be pulled back from the RF components due to unwanted parasitic effects(e.g. stray capacitance) to ground. For an indication of how much, please see the reference design files.

    • 16MHz looks fine

    The SWCLK and SWDIO(pin 23 and 24) should be kept away from the antenna an RF parts. Make sure to ground C4 thoroughly. It's hard to see from your file if the tap of your antenna is grounded or not(no visible vias), it should be grounded.

    Another note is that when you upload your layout it is a lot easier to see what's going on if you include vias. If possible upload full design files.

    Best regards,

    Øyvind

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