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Original question:

AWR2243: what`s the requirement for Wilkinson power divider ？

AWR2243: the requirement for group delay of Wilkinson power divider

xu qingjie
Intellectual 320 points
Part Number: AWR2243
Other Parts Discussed in Thread: MMWCAS-RF-EVM

Hi supporter ；

happy NewYear！

We are simulating the Wilkinson power divider，and the group delay is about 300ps.

is this fine ？ could you please offer me the simulation data of  MMWCAS-RF-EVM？

  • 0
    TI__Mastermind 31680 points

    Hello Xu,

    Due to year end holidays, there might be a delay in our response. Sincere apologies for the inconvenience caused. We will review your query and get back to you next week.

    Wishing you a very Happy New Year.

    Regards,

    Ishita

  • 0
    TI__Guru 58035 points

    Hello Xu Qingjie,

    Wishing you too a very Happy New Year !.

    The absolute delay on the 20Ghz sync path does not matter much. What is of concern is the mismatch between the delays between the path to all the devices. Any mismatch between the paths causes mismatch in the sync between the devices. Typically we try to keep the mismatch within 15ps.

    Regards,

    Vivek

  • 0 in reply to Vivek Dham
    Intellectual 320 points

    Hi Vivek；

    thanks for your reply;

    Q1:  What will happen if the mismatch is large,exg 200ps？ impact  TX beamforming performance？

    Q2:  Our own cascade board is very large，the LO path is long，and if we keep the LO path equal length,we may can not keep the mismatch within 15ps.

    So if we need  keep the mismatch within 15ps by simulation,the length may be not equal. Is it fine？

    thanks

  • 0 in reply to xu qingjie
    TI__Guru 58035 points

    Hello Xu Qingjie,

    Q1) If the mismatch is large then the pages mismatch between the channels of the difference devices would impact Tx beam forming and angle estimation.

     Q2) Typically if the length is matched then the delay is also matched. Could you provide more details on why same length is giving you different delays?

    Regards,

    Vivek

  • 0 in reply to Vivek Dham
    Intellectual 320 points

    Hi Vivek；

    thanks for your reply;

    Q1) If the mismatch is large then the pages mismatch between the channels of the difference devices would impact Tx beam forming and angle estimation.

    reply: could calibration fix this issue？

     Q2) Typically if the length is matched then the delay is also matched. Could you provide more details on why same length is giving you different delays?

    reply:The LO path is long on our board.Some path need more turnings to keep equal length,and different turnings on different path lead different phase mismatch .

    Take MMWCAS-RF-EVM for example.On our own board,the blue path has more turnings than the red path to keep equal length,we simulated this by HFSS&CST.,and found out different delay on the two path.  Do you suggest us equal length or same delay？

    thanks

  • 0 in reply to xu qingjie
    TI__Guru 58035 points

    Hello Xu,

    Q1) If there is a large delay mismatch between the LO paths then the phase mismatch between the devices would vary with RF frequency. So in a single chirp the phase mismatch would vary as the RF frequency changes. So it might not be easy to calibrate this out. If the chirp is very narrow (small RF frequency change) , then you could possibility approximate the phase mismatch to a fixed value and correct for it.

    Q2) Ok, you have routing in multiple layers. Ideally you need to match the lengths on each layer. For example the length on L1 should be matched for each paths and then length on L3 should be matched on each of the paths. Then you will have both length matched and delay matched. If that is not possible then the total delay needs to be matched.

    Regards,
    Vivek