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IWR1642BOOST: EVM antenna dimensions don't fit the design files / compliance

Massimo Liistro
Prodigy 190 points
Part Number: IWR1642BOOST
Other Parts Discussed in Thread: IWR1642

Dead Support,

I have noticed that the antenna/transmission lines dimensions given in the design files (Altium or Gerber) don't fit the actual dimensions of the EVM.

For example, at the transition from GCPW to microstrip (see figures), the thinnest side is 47.1µm(~2mils) wide while the design files define 100µm (4mils).

I understand these design files are valid for the correct stackup (RO4835, correct thickness ...).

Does it mean the evaluation boards do not use the stackup given in the design files ? Or that the design files are not valid ?

Finally, I've read in :

https://e2e.ti.com/support/sensors/f/1023/p/774718/2866934?tisearch=e2e-sitesearch&keymatch=blind%2525252520spot%2525252520iwr1642#2866934

that « IWR1642 is not regulation compliant », does it mean that it cannot be used to develop any product requiring FCC/CE certification ?

Thank you,

Massimo

  • 0
    TI__Guru 50240 points

    Hi Massimo,

    I've asked an expert to look into this and we should have an answer for you in the next few days.

     

    Cheers,

    Akash

  • 0 in reply to Akash Gondalia
    TI__Mastermind 25835 points

    Hi Massimo,

            Is there any application you are targeting? Are there any concern based on this?

     You are right, correct design target is 4mils, However PCB manufacturer will have typically +/-1 to 1.5mil variation in their etching process for large quantity of boards. Design/System performance is tolerant to this variation. Typically these etching will not be steep, but it would be trapezoidal in nature.  I'm not sure about measurement methodology and accuracy of the measurements.... Here by looking at the diagram, it appears it has been  slightly over etched.

    On the regulation compliance, IWR1642 is a 77-81GHz frequency band;  for people counting application from Regulation perspective 60-64GHz frequency is used. However there is lot of displacement sensing application IWR1642 devices are being used.  And EVMs have gone through European RED certification process (Detailed link is given below) & compliant to CE you could see marking on the EVM. 

    http://www.ti.com/lit/ml/sszq069a/sszq069a.pdf

    Thanks and regards,

    CHETHAN KUMAR Y.B.

  • 0 in reply to CHETHAN KUMAR Y.B.
    Prodigy 190 points

    Hello CHETHAN KUMAR Y.B,

    Thanks for your detailed answer.

    Indeed the width I gave is the top of the trapeze, the bottom is a wider.

    We would like to develop fixed road traffic management radars : traffic counting ( +  speed measurements, ...) and also people counting.

    My understanding is that, following regulations, IWR1642 is OK for traffic counting if we use 1GHz bandwidth: 76-77GHz (see attached picture, 77-81 is for automotive).

    But it is not allowed for people counting.

    As far as I understand, the European legislation gives only 500MHz bandwidth in the 60-64GHz  band (61-61.5), can you confirm ?

    Best regards,

    Massimo

  • 0 in reply to Massimo Liistro
    TI__Mastermind 25835 points

    Hello  Massimo, 

         Thank you for sharing your application. 

    Yes, your understanding is correct i.e. IWR1642 is OK for traffic counting if you use 1GHz bandwidth.  Yes, for people counting 60GHz frequency band is recommended. 

    Yes, Currently in European legislation gives only 500MHz bandwidth in ISM band, This is mainly to allow higher output power between 61-61.5GHz band. 

    Different geographical regions have different regulatory requirements. We encourage you to check with the notified regulatory body at respective location to know latest updates on this front, as these specs are also keep evolving to support different applications.

    Thanks and regards,

    CHETHAN KUMAR Y.B.

  • 0 in reply to CHETHAN KUMAR Y.B.
    TI__Mastermind 25835 points

    Hi Massimo,

        Did this answers your question?

    Thanks and regards,

    CHETHAN KUMAR Y.B.

  • 0 in reply to CHETHAN KUMAR Y.B.
    Prodigy 190 points

    Hi CHETHAN KUMAR Y.B,

    Thank you for your help.

    I will stay informed about the regulations.

    Best regards,

    Massimo