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Original question:

IWR6843ISK: elevation or 3D (elevation + azimuth) beamforming capabilities

IWR6843ISK: beam forming (3D) vs TX power of each antenna

Bart
Expert 6460 points
Part Number: IWR6843ISK

This is a related question to the attached thread.

If we have the following case:

  • Single antenna operation (e.g. TDM MIMO) – we get 110 degrees FOV in azimuth with probably 6.8Bi gain? (http://dev.ti.com/tirex/explore/node?node=ANS49gohN4gX2.NvHAAGGQ__VLyFKFf__LATEST)
  • 2 TX beamforming (same phases for TX1 and TX3) – how much FOV and dBi do we get, I guess beamwidth should be narrower (smaller FOV) with higher peak gain?
  • 2 TX beam steering (adjusting phases for TX1 and TX3) – I guess at any steered azimuth angle the energy should be higher than energy of single antenna at corresponding azimuth. Are there any measurements (of radiation patterns) done for individual steering angles?

We just want to make sure – using 2 antennas simultaneously, does the IWR chip radiate twice more energy than using only one antenna? And correspondingly 3TX operation 3x more energy?

Thanks for clarifying.

  • 0
    TI__Mastermind 40495 points

    HI, 

    Yes, 2TX beam-forming should give you 6dB gain at the steering angle.   But of course the beam will be much narrower.  The beam-width is about 20 degree considering a 6dB bandwidth.   But we have not measure the radiation pattern with TX beam-forming yet.   If you want to use TX beam-forming to cover a wider FOV, you need to steering the beam for different angle and stitching the results together.  

    The 3TX beam-forming will provide about 9.5dB gain at the steering angle.   

    Best,

    Zigang

  • 0 in reply to zigang Yang
    TI__Expert 6460 points

    Hi Zigang,

    thanks, it helps. One question though - does the 6dB you mentioned representspower (thus means four-times more power) or voltage (meaning twice more power)?

    Also looking at antenna patterns (e.g. section 3.5 http://www.ti.com/lit/ug/swru546b/swru546b.pdf). It calculates with half points at 6dB (12dB in combined diagram). Does it mean that diagrams depicts logarithmic voltage/amplitude rather than power? Because, in case of power, the half point should be at 3dB (or 6dB in combined diagram).

    Thanks for explaining.

  • 0 in reply to Bart
    TI__Mastermind 40495 points

    HI, there:

    Usually we use 20*log10(amp) and 10*log10(power), therefore, 6dB is always means

    4 times in power and 2 times in amplitude. 

    Best,

    Zigang