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AWR1642: the problems about Antenna coupling

Rata Zhang
Expert 2840 points
Part Number: AWR1642

Hi,

 In the follwing URL:

https://e2e.ti.com/support/sensor/mmwave_sensors/f/1023/t/623489?tisearch=e2e-sitesearch

1.Anil said "Antenna coupling is the direct coupling of the Tx antenna signals to the Rx antenna" in the Dss demo.In the Antenna design,the distance between Rx antennas is Lambda/2 and the distance between Tx antenna and Rx antenna is 8.77mm. The coupling between Rx antennas is more serious than that between Rx and Tx antennas in theory. Why is only antenna coupling  between the  Rx and Tx antennas considered in the DSS demo?

2.In the demo, antenna coupling dominates the range bins close to the radar,I don't understand that.Is there any related material for reference?

Thanks in advanced,

Regards,

Rata

  • 0
    TI__Guru*** 148804 points
    Hi

    As I mentioned in the your other thread, please search for "antenna coupling signature"

    We are also working to provide you with more references

    thank you
    Cesar
  • 0 in reply to Cesar
    TI__Mastermind 18500 points
    Hi Rata,

    The specific DSS demo feature you are referencing "calibDcRangeSig" only tries to calibrate out close TX/RX coupling response.

    While RX to RX coupling is an issue, I think you have to look at this from a radio link budget perspective. The TX is the dominant coupling aggressor in the system. The resulting overall power from the incoming incident wave is much smaller than the outgoing power from the TX. Additionally, any power that does couple from RX to an adjacent RX will be only a small fraction of the received power - the majority being transmitted down the GCPW to the RX chain. So overall, the coupled RX to RX will be a very small.

    If you are interested in signals close to the noise floor, this could be an issue. Likewise, it is an issue for phase dependent measurements like direction of arrival. This is where calibration of the gain and phase of the RX path needs to be performed. One good paper from our systems team here: ieeexplore.ieee.org/.../stamp.jsp

    Please let me know if that answers your questions on this topic.

    Thank you,
    Randy