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MMWAVE-STUDIO: Tx Beamforming at mmwave studio using IWR6843ISK

John Park
Prodigy 90 points
Part Number: MMWAVE-STUDIO
Other Parts Discussed in Thread: IWR6843ISK

Hi, I am trying Tx beamforming using IWR6843ISK, DCA1000 and mmWaveStudio. I am using 2 tx(Tx0, Tx2)

I have 3 qusetion about Tx beamforming. 

1. 

theta_desired = 60;
m_ind = [0 1 2];
phaseInc = 5.625;
phaseTX_rad = 2*pi*(m_ind*sind(theta_desired));
phaseTX_deg = (phaseTX_rad)*180/pi;
phaseTX_deg_wrap = wrapTo360(phaseTX_deg);
phaseShifter = round(phaseTX_deg_wrap/phaseInc)*phaseInc;

Base on abvoe code when we try to aim at 60 degree phase shfiter value is [0  311.7691  623.5383]. In mmwave studio we can't enter value that is over than 360 . In ohter question, they put phaseTX_deg_wrap value in mmwave stuido which is [0  311.7691  263.5383]. I was wondering if it is okay to use phaseTX_deg_wrap  value.

2. From what I understand, Tx Beamforming is achieved through the signal transmission delay of Tx antennas. Does phase shift value in mmwave stuido lower value mean it's Tx antenna is sending the signal faster?

 

3. If  question 2 is correct,  when I try to aim at -60 degree than is it okay to use phase shift value like [623.5383 311.7691 0] ? cause this value means Tx3 transmit first and then Tx1 transmit signal next. Then it will aim opposite side of Phase Shfiter value of  [0  311.7691  623.5383] .

Thank you.

  • +1
    TI__Mastermind 40335 points

    Hi, there:

    Please see my answers inline.

    theta_desired = 60;
    m_ind = [0 1 2];
    phaseInc = 5.625;
    phaseTX_rad = 2*pi*(m_ind*sind(theta_desired));
    phaseTX_deg = (phaseTX_rad)*180/pi;
    phaseTX_deg_wrap = wrapTo360(phaseTX_deg);
    phaseShifter = round(phaseTX_deg_wrap/phaseInc)*phaseInc;

    Base on abvoe code when we try to aim at 60 degree phase shfiter value is [0  311.7691  623.5383]. In mmwave studio we can't enter value that is over than 360 . In ohter question, they put phaseTX_deg_wrap value in mmwave stuido which is [0  311.7691  263.5383]. I was wondering if it is okay to use phaseTX_deg_wrap  value.

    [ZY] Yes, you are right,  you will need to wrap any angle to [0,360], and programming the phase shifter value.   But you need to enable all three TX antenna, instead of TX0 and TX2 only.

    From what I understand, Tx Beamforming is achieved through the signal transmission delay of Tx antennas. Does phase shift value in mmwave stuido lower value mean it's Tx antenna is sending the signal faster?

    [ZY]  The phase shifter could be implemented by adding a very small delay.  I am not sure.  But mathematically, please just assume that it is phase rotation.

    3. If  question 2 is correct,  when I try to aim at -60 degree than is it okay to use phase shift value like [623.5383 311.7691 0] ? cause this value means Tx3 transmit first and then Tx1 transmit signal next. Then it will aim opposite side of Phase Shfiter value of  [0  311.7691  623.5383] .

    [ZY]  The phase shifter can only programmed from [0, 360].   As I said, please just assume it is a phase rotation mathematically.  Therefore, 623.5383 equals 263.5383. 

    Best,

    Zigang