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CC2652P: 20dbm Antenna for CC2652P1FRGZR

Francisco Zamudio
Prodigy 80 points
Part Number: CC2652P
Other Parts Discussed in Thread: LP-CC2651P3

Tool/software:

Hello Team,

I am working with a new application and I am using the CC2652P1FRGZR considering the 20dbm PA. So, I have a couple of questions for that:

  • Does the antenna type selection for this PA should be a PCB antenna? I was considering a chip antenna, but it seems insufficient for that PA. The antenna that I am considering as a chip antenna is the 2450AT45A0100001E. If that is not a good option, I am considering this PCB antenna https://www.ti.com/tool/LP-CC2651P3, but it would be nice to have a smaller one because the application would be for a wearable. Do you have any other recommendations?
  • If I use the PCB antenna, would be needed to have all of this area clean? (Green)
  •  

  • Can you please help me review my schematic as well?

Thanks!!

Francisco

  • 0
    TI__Guru**** 171094 points

    Francisco,

    Francisco Zamudio said:
    Does the antenna type selection for this PA should be a PCB antenna? I was considering a chip antenna, but it seems insufficient for that PA

    The PCB antenna is the low cost choice but nothing blocks you from using the chip antenna you linked. The model you linked can work for the 20 dBm configuration (its specifications mention 3W max).

    Francisco Zamudio said:
    If I use the PCB antenna, would be needed to have all of this area clean? (Green)

    If your image accurately reflects your final design, you will have to clear not only the green area but also all areas around the inverted F antenna.

    The PCB image is incomplete but please be sure to make your design as close as possible to our LP-CC2651P3 reference design for the best chance of having a good performance on your radio - especially with the +20 dBm high power path.

    Also, please check our design guidelines document CC13xx/CC26xx Hardware Configuration and PCB Design Considerations (SWRA640) for all relevant aspects of PCB and schematics design.

    Francisco Zamudio said:
    Can you please help me review my schematic as well?

    Regrettably the image has low resolution, but one thing I can see is that it uses a Johansson IPC 1720BL15B0050. This balun does not mention a match to the CC26xx family of devices. In this case, if you haven't done so, I would consult with the manufacturer to see if this balun is suitable for this application.

    The application note below has our recommendation for the IPC part from Johansson.

    https://www.ti.com/lit/an/swra572/swra572.pdf

    Hope this helps,

    Rafael

  • 0 in reply to desouza
    Prodigy 80 points

    Hello Rafael,

    Thank you so much for your answer! I appreciate it. 

    My main concern about the antenna selection is that it won't support the distance that I am looking for (about 100m). This application would be on the exterior, on something like a football field. Maybe my question was wrong, but I would like to use the PA to reach that distance without a problem. I also would like to pass the FCC validation. 

    For the PCB I was planning to create a shield with vias (purple section), the board doesn't have too much area, so, using this big antenna makes it hard to have that area clean. I've been thinking about something like this 

    It would be nice if we could schedule an appointment to review this one quickly. 

    Please, let me know. 

    Regards

    Francisco

  • 0 in reply to Francisco Zamudio
    TI__Guru**** 171094 points

    Francisco,

    Francisco Zamudio said:
    My main concern about the antenna selection is that it won't support the distance that I am looking for (about 100m).

    There are many factors that can affect the maximum range of a system, starting with the antenna but also with surrounding factors (direct or indirect line of sight, with/without interference, proximity with large metallic objects, etc.).

    We have a range estimator calculation tool that uses the Friis equation and allows you to explore the number of variables involved in this problem

    https://www.ti.com/tool/download/RF-RANGE-ESTIMATOR

    Also, a study for the various antennas is shown in the Antenna selection guide AN058 (SWRA161) application note, where the benefits and tradeoffs for the PCB and the other types of antennas is explored.

    Francisco Zamudio said:
    For the PCB I was planning to create a shield with vias (purple section),

    In our experience we found out that, for +20 dBm, the design indeed requires a shield on the device, balun and limit the GPIO pin connections outside of the shielded area to meet FCC restrictions. However, as shown in the 2.4GHz Inverted F (SWRU120) application note, it is not desirable to have ground or parts near the end points of the antenna.

    Hope this helps,

    Rafael

  • 0 in reply to desouza
    Prodigy 80 points

    Hello Rafael,

    Thank you so much! this is very useful information. 

    So, according to your feedback, I've decided to return to the chip antenna. Can you please double-check on that? This is the antenna section

    and this is the complete uC section

    This is the current floorplan (fig 3). Fig 4  in yellow shows the charger connector and the GND connector is below the capacitors and inductor of the 2.4GHz track. 

    Fig 5 shows the R21 and R22 connection, I would like to see your feedback about it. 

     

    Thanks!

    Francisco

  • 0 in reply to Francisco Zamudio
    TI__Guru**** 171094 points

    Francisco,

    Given this discussion seems to be evolving to a complete design review, I would prefer that you submit your design on the URL below for a more thorough evaluation.

    https://www.ti.com/tool/SIMPLELINK-2-4GHZ-DESIGN-REVIEWS

    It is important to have a complete design and routed layout, so we can provide the best assessment.

    Best regards,

    Rafael

  • 0 in reply to desouza
    Prodigy 80 points

    Great! sounds good!! I'll submit the documentation when I complete it. 

    Thanks!!

    Francisco