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Original question:

LAUNCHXL-CC2640R2: The AOA test result with CC2640R2 and BOOSTXL-AOA

LAUNCHXL-CC2640R2: the result of antenna pairs compensation isn't liner for added antenna

Andy Yang78
Intellectual 380 points
Part Number: LAUNCHXL-CC2640R2
Other Parts Discussed in Thread: BLE-STACK

Dear Sir

We are using our own  antenna on the CC2640R2 and trying to find the suitable offset and gain for each antenna pair.

We measure the antenna pair compensation and the result isn't liner, therefore we are unable to calculate the offset and gain.

Is there any factor we can check first? such as distance (5cm) between the antennas, the switch time for each antenna, etc.

  • 0
    TI__Mastermind 39860 points
    Andy,

    Not sure what you are trying to do here. Antennas are usually specified with efficiency, directivity and gain. By "offset" do you actually mean "efficiency"? Efficiency (n) is the relation between the total radiated power (TRP) and the input power (Pin) delivered to the antenna; n = TRP/Pin. The gain (G) is given by n x Directivity, where Directivity = Peak EIRP/TRP.

    The antenna gain and efficiency is measured in an anechoic chamber.

    Could you please elaborate on what you are trying to achieve and how you perform the measurements?

    BR,
    Sverre
  • 0 in reply to Sverre
    Intellectual 380 points

    Dear Sverre

    According to following document

    BLE-Stack User's Guide --> Angle Compensation

    Under AoA_getPairAngles(), we will acquired the angle based on I and Q data. After that, angle compensation is added. 

    As you can see from the image below, the offset is applied to make sure the data received at 0 degree will derive 0 degree after the calculation and then the slope is changed to make it fit better with all the rest of the angles.

     

    ../_images/lab_tuning.png

    Since we use our own antenna, we need to find the offset and gain for each antenna pairs, such as antenna pair 1-2, 2-3 and 1-3.

    For my understand, we need to get the yellowing first in order to calculate the offset and gain.

    Unfortunately, the result of angle measurement isn't liner (unlike the yellow line), therefore we aren't able to get antenna pairs compensation.

    This is why we submit this case and ask for the possible factor for the non-liner measure result for each antenna pairs.

    BR,

    Andy

  • 0 in reply to Andy Yang78
    TI__Guru 56215 points
    Hi,

    The tuning example we used in our SDK is just an example. A more advanced version might benefit your case more. But at least what you can do is to make sure when you place the transmitter and the receiver at zero degree, you can get a angle result with zero degree.

    Also when you are finding those parameters, please make sure your test environment is ideal first(like in a EMC chamber to minimize the multi-path reflection)

    It's not realistic to find all the parameter in a not controlled environment.