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Original question:

WL1831: reference design help

WL1831: WL1831MOD reference design

Hao Meng
Prodigy 150 points
Part Number: WL1831

May I know if there is any update please?  Thanks.

  • 0
    TI__Expert 6180 points

    Hi Hao Meng,

    I could not find the full reference design using the W3006, although you may also use another antenna as long as; 

    - The Antenna is of same type
    - Gain is equal to or less than certified antenna
    - out-of-band emissions are similar - you might need a regulatory house to look into this

    As seen in our WL18xx Module Hardware Integration Guide (lit# SWRU437) the following table shows the approved antenna types.

    For more information you can also see our Antenna Impedance Measurement and Matching Application Note.

    BR,

    Jessica M. Torres

  • 0 in reply to Jessica M. Torres
    Prodigy 150 points

    Thanks for the update. There are a few points I would like clarified please.

      

    The FCC RF test reports specifies a particular chip antenna from TDK and Pulse, see the following list:

     

    Table 5 from the hardware integration guide (email below) states that any chip antenna from TDK or Pulse can be used with the existing FCC/IC authorisation, so long as the maximum gain values are not exceeded.

     

    Question: Am I not restricted to use only the antennas tested for the FCC RF test report?

     

    Antenna matching components:

     

    The reference schematic uses TDK ANT016008 and identifies the matching component values as being matched for the module:

    Question: Might the values need to change for a different chip antenna?

    Question:  If yes, what values were used for the W3006 antenna?

    Question: Are the component values also affected by the PCB layout?

      

    Out of band emissions:

    Question: What specifically needs to be checked in, for example, FCC part 15C?

     

    Thanks,

  • 0 in reply to Hao Meng
    TI__Expert 6180 points

    Yes you may use an antenna from another manufacturer, however the following rules apply when deviating from the certified list:; 

    - The Antenna is of same type (chip, whip, etc)
    - The gain is equal to or less than the certified antenna
    - out-of-band emissions are similar 


    The last point is the one the regulatory test house will look at to ensure there is no significant difference in performance. The "Significant" part is what the test house will determine. 

    The Reference design does show the matching component values used for antenna impedance matching, but these components will change depending on your PCB Layout. There are many factors that will change the impedance like length of your transmission line, substrate thickness, etc.  A good reference to read more about this is in our Antenna Impedance Measurement and Matching Application Note (https://www.ti.com/lit/pdf/swra726).

    Here is another good reference on antenna matching https://www.embedded.com/integrating-chip-antennas-into-a-pcb-understanding-antenna-matching/ 

    BR, 

    Jessica M. Torres

  • 0 in reply to Jessica M. Torres
    Prodigy 150 points

    Hi Jessica, 

    As you mentioned Yes you may use an antenna from another manufacturer, however the following rules apply when deviating from the certified list:; 

    - The Antenna is of same type (chip, whip, etc)
    - The gain is equal to or less than the certified antenna
    - out-of-band emissions are similar 

    Currently we are using the ANT016008 antenna using your reference PCB layout. This antenna is becoming obsolete.

    The W3006 antenna is on the certified list. It is physically larger and would require a new PCB layout. Because I am not deviating from the certified list, does this mean I do not have to worry about out-of-band emissions or tuning the new PCB layout?

  • 0 in reply to Hao Meng
    TI__Expert 6180 points

    Whichever new antenna you use will require new Matching Components depending on the observed reflections on the transmission line of your PCB. Although you will not have to worry about re-testing for the out-of-band emissions.

    BR.

    Jessica M. Torres