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IWR6843: Antenna geometry parameter for 6843 device

HOGYUN RYU
Intellectual 330 points
Part Number: IWR6843
Other Parts Discussed in Thread: IWRL6432

Hello, TI engineers.
I had developed IWRL6432, and now I am investigating about IWR6843.

Before my question, I asked about antenna geometry of 6432 in the thread of follow link, IWRL6432: Modifying antenna geometry support in 5.2 SDK
In the thread, Mr. Dye tought me about Antenna geometry configuration parameter.

Currently, I have checked there is no information of the similar parameter in documents(such SDK user guide) for 6843.
Just I couldn't find it?

I would like know I can handle MIMO ant position through designing custom antenna by myself.
Are there parameters for IWR6843 such as antDistX or antDistZ parameter in the CLI for 6432.

Regard.

  • 0
    TI__Mastermind 20681 points

    Hello, 

    For 6843, antenna geometry structures are defined in antenna_geometry.c (<MMWAVE_SDK3.X_INSTALL_DIR>/packages/ti/board). You will need to define your custom antenna. Please see AoA documentation at <MMWAVE_SDK3.X_INSTALL_DIR>/packages/ti/datapath/dpc/dpu/aoa2dproc/docs/doxygen/html/index.html, the section "Antenna Geometry Definition" should help you understand the relationship between the physical antenna and the definition in C code.

    Best Regards,

    Josh

  • 0 in reply to Josh Dye
    Intellectual 330 points

    Hi, thanks for your answer.

    My quriocity is halfly solved through your reply.

    I briefly checked the documentation you linked.
    And I understand about just geometry things.

    What about antenna distance parameters(antDistX and antDistZ)?

    In according to the definition, it seems to that the antenna position offset is fixed as multiples of half lamda.

    Is it possible to modify and design custom antenna with any offset value not with multiples of half lamda?

    Regard

  • 0 in reply to HOGYUN RYU
    TI__Mastermind 20681 points

    Hello,

    HOGYUN RYU said:
    What about antenna distance parameters(antDistX and antDistZ)?
    gAntennaSpacing is used to specify the distance between antenna elements. It is assumed that the spacing in elevation and azimuth is equal so there are not separate variables as in 6432. 
    HOGYUN RYU said:
    Is it possible to modify and design custom antenna with any offset value not with multiples of half lamda?
    Lambda/2 is the typical value used but it is not required; however, using a value other than labmda/2 will affect angular FOV and accuracy. For more information please refer to section 2.3 (Angular Range and Resolution) of this application note. 
    Best Regards,
    Josh
  • 0
    Intellectual 330 points

    Thanks for your answer.

    Then, my worry about designing custom antenna becomes deeply hard.

    All antenna of EVM's is performed like single patch antenna for each in horizontal direction.
    It it not difficult to design while the spacing is half lamda.

    But, the single patch antenna has 120 degree full angle FOV like as EVMs have.
    I want to design an antenna which has narrower FOV than 120 degree.

    As you know about antenna design principle, narrow beam angle is made from array element(in horizontal direction in this case).
    It seems to be physically impossible to make narrower FOV antenna using array element with half lamda spacing between each T/Rx in horizontal axis.

    My challenge is overcome this difficulty.

    Do you have any idea for it?
    Or is there no other customer who has the same issue as mine?

    Let me know if you have any possible method.

    Regard

  • 0 in reply to HOGYUN RYU
    TI__Mastermind 20681 points

    Hello, 

    We are looking into you question. Please allow some time for us to respond here. 

    Best Regards,

    Josh

  • 0 in reply to HOGYUN RYU
    TI__Genius 9630 points

    Hi,

    Parallel feed antenna array can be used to achieve this. There is currently no TI reference design available with a FOV that is narrower than 120 degrees.

    Regards

    Ankit

  • 0 in reply to Ankit Mohanty
    Intellectual 330 points

    Hi,

    I surely recognize there is no TI reference design for it.

    Just I want to know whether this is only my own issue or I can take help from you
    (by designing horizontally wide custom antenna array for 6843 even though the antenna offset had not multiple of half lamda).

    And, I want to sure that no parameter or CLI or code like antDistX/antDistZ in 6843.
    Do I understant right?

    Thanks.

  • 0 in reply to HOGYUN RYU
    TI__Genius 9630 points

    Hi,

    Please kindly check the below thread similar to your concern:

    (+) AWR1843BOOST: Regarding Beam narrowing - Sensors forum - Sensors - TI E2E support forums

    You can check the below package for changing the antenna geometry to achieve narrow bandwidth as Josh pointed out:

    mmwave_sdk_03_06_00_00-LTS\packages\ti\board\antenna_geometry.c

    JOSH: "For 6843, antenna geometry structures are defined in antenna_geometry.c (<MMWAVE_SDK3.X_INSTALL_DIR>/packages/ti/board). You will need to define your custom antenna. Please see AoA documentation at <MMWAVE_SDK3.X_INSTALL_DIR>/packages/ti/datapath/dpc/dpu/aoa2dproc/docs/doxygen/html/index.html, the section "Antenna Geometry Definition" should help you understand the relationship between the physical antenna and the definition in C code."

    Regards

    Ankit