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CC2652P7: Zigbee Antenna Issues

Eren Gül
Prodigy 10 points
Part Number: CC2652P7

Tool/software:

Hi everybody,

I am really frustrated right now, because my custom layout does not work as intended.

What I have did was copying the hardware guide (I know its not the best solution, but for me its the only one for now), 
and I am not able to bind any kind of zigbee devices to this module. I am using in parallel multiple RF-BM-2652P7 chips, and those are working great, so I tried my best to match 50 Ohms impedance (the antenna it self is rated at 50Ohms).

Does anybody know what my mistake is=? I use the same antenna for my ESP32-S3 and it works great.

BR

Layout

Schematic

  • 0
    TI__Guru**** 170454 points

    Hi,

    Where did you get the part values from the Balun and the output filter? The reason of my question is that they are vastly different than what we use in our reference design for the CC2652 part - check the design files of the LP-CC2652R7 board. Despite the device is different on this Launchpad, your design only uses the +5 dBm path which corresponds to this board.

    If you want to use external bias, you can also use the +5dBm path of the LP-CC1352P7-4 board as a reference - check its design files here.

    Regardless of these differences, the inability to connect might be due to either a failure on the device or a SW problem.

    Can you connect a piggy back just before the antenna and use SmartRF Studio to perform conducted measurements on a Spectrum Analyzer? This will tell you if there is at least signal on the antenna feed.

    As for the PCB drawing, I don't see anything striking that could be causing all your problems.

    Hope this helps,

    Rafael

  • 0 in reply to desouza
    Prodigy 10 points

    Hi, 

    thank you for your response. - You are right, got the values from ChatGPT since I didn't knew how to calculate the Balun and output filter.

    I think I got the wrong reference design above. Thank you - I will try that out ! 


  • 0 in reply to desouza
    Prodigy 10 points



    Matched it as much as possible, is there any way to simulate it without.a VN Analysing hardware? 

  • +1 in reply to Eren Gül
    TI__Guru**** 170454 points

    Hi,

    Simulation tools exist (Keysight ADS, Ansys, HFSS, etc.) and can be used to have an approximate response to the performance of your system. For that you would need to have not only circuit simulation but also EM for the irradiated behaviour of the antenna. One additional aspect is to have part libraries (such as Murata, or Coicraft) that have distributed simulation models for the passive parts used in the filter and balun. 

    Even still, the simulation will still have many ideal parameters that are not easily modeled, such as the various physical manufacturing and parts assembly such as quality of soldering, board and copper thickness variations, choice of parts, etc. This is the main reason why we publish our reference designs with full CAD sources, so you can copy an already validated RF design. 

    This is valid also for the antenna matching, which needs to be tuned with the surroundings (enclosure, product placement, etc).

    Overall, the use of test equipment such as a VNA, Spectrum Analyzer, etc. will be very important during the product development. 

    Hope this helps,

    Rafael