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CC1352R: AN043 antenna matching for Bluetooth

Hiago Santos da Gama
Prodigy 230 points
Part Number: CC1352R
Other Parts Discussed in Thread: CC2511, ,

Hello,

I am currently working with the CC1352R MCU and I need a PCB antenna in order to use its Bluetooth. As I am developing the PCB using KiCAD, I saw that the AN043 (SWRA117D) footprint is available in its library and I was willing to use it, but I don't know if it's necessary to place some components between the MCU and the antenna for matching purposes. According to the AN043 datasheet, "The PCB antenna on the CC2511 USB dongle reference design is a meandered Inverted F Antenna (IFA). The IFA was designed to match an impedance of 50 ohm at 2.45 GHz. Thus no additional matching components are necessary". 

Does that mean that no components need to be placed between CC1352R and AN043 in order to connect them? If so, I would like to know if there is a safe distance that can be applied between the MCU and the antenna, since the trail would change the impedance in the circuit.

Thanks for the help,

Hiago Gama.

  • 0
    TI__Genius 11810 points
    Hello Hiago,

    The antenna AN043 is a small footprint 2.4 GHz antenna. If you are using CC1352R you'll need a sub-1 GHz antenna as well if you intend to enable sub-1 GHz operation. CC1352R does not have 50 ohms output impedance and therefore needs a matching network and a balun (if used in differential mode) between the chip and antenna. Additionally, we recommend to add antenna matching components close to the antenna, in case the antenna impedance will shift when you put your board in a casing etc.

    If you only want to support 2.4 GHz operation you should do some modifications to the reference design (LAUNCHXL-CC1352R1);
    * A1 should be replaced with AN043
    * Make footprints for Z60-Z63 but let Z60 and Z63 be 0 ohm in your initial design. You'll then be able to match your antenna when you product is mounted in the final case (if applicable).
    * Remove U28 and connect the R16 node directly to C482. R16 can be skipped.

    -Simon
  • 0 in reply to Simon J
    Prodigy 230 points
    Hi Simon,

    Thank you very much for your help! Just another question, what is the antenna used in the reference design of LAUNCHXL-CC1352R1? Is it the DN024 antenna?

    Best Regards,

    Hiago
  • 0 in reply to Hiago Santos da Gama
    TI__Genius 11810 points

    Hi Hiago,

    On the LAUNCHXL-CC1352R1 we use a shorter version of DN024 (L4 is shortened to the silkscreen mark, ref. DN024 design note) to be able to use it for 868 MHz, 915 MHz and 2.4 GHz. Note that the Design Note DN024 is not up to date with this "tri band" antenna. Please refer to the design files for LAUNCHXL-CC1352R1 for more details.

    -Simon

  • 0 in reply to Simon J
    Prodigy 230 points
    Thank you, Simon!

    I decided to use the DN024 design since it can be used with sub one and 2.4 GHz. I am using the matching components according to its datasheet. Hopefully, I will be able to use it properly.

    Best regards,

    Hiago