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Original question:

IWR6843: Antenna related question

IWR6843ISK: Radiation pattern measurement and calculation of dBFS

Katsuhiro Miyamoto
Expert 1460 points
Part Number: IWR6843ISK
Other Parts Discussed in Thread: MMWAVEICBOOST, IWR6843

Hello support team,

Could you please explain more detail of radiation pattern measurement of ISK antenna?
dBFS value of Bore-sight is about 96 by looking at Figure 41 to 46 in mmWaveICBoost and Antenna Module User's Guide.
How ~96dBFS is measured?
Is it measured by IWR6843?
How ~96dBFS is calculated?
In case of conventional radiation pattern measurement, E(I)RP at test antenna is measured only by TX side. Assuming that TX output power is known, antenna gain is obtained by comparing to reference antenna.
"Here corner reflector is kept at bore-sight and Radar is rotated in Azimuth/Elevation planes and measurement is plotted across Tx and Rx combinations. " seems to indicate that received signal strength is measured and plotted to get radiation pattern.

Best Regards,
Katsuhiro

  • 0
    TI__Guru 50240 points

    Hi Katsuhiro,

    I've asked an mmWave Expert to look into this query and someone should have an answer for you in the next few days.

    Cheers,

    Akash

  • 0 in reply to Akash Gondalia
    TI__Mastermind 25835 points

    Hello, 

        You are right, In case of conventional radiation pattern measurement, E(I)RP at test antenna is measured only by TX side. Antenna gain is obtained by comparing to reference antenna.

    For the Radiation pattern measurement on the user guide is done using a corner reflector at a know distance from the radar. The reflected power is measured using ADC. This measurement is repeated for Azimuth orientation form -60 to 60 Deg and for elevation orientation it is measurement from -30 deg to 30 deg. Keeping bore sight as a reference value, Radiation pattern is plotted either side of bore sight. As this measurement includes Tx and Rx sides of the radiation pattern, However antenna on Tx side and Rx sides are identical.  96dBFS is not an absolute number it's a relative number, As this include both Tx and Rx Radiation patterns. For the 6dB beam width you could subtract 12dB (Due to Tx and Rx are together) from the bore-sight. 

    For Absolute Tx or Rx antenna Radiation pattern measurement you could look at the below post. 

    http://e2e.ti.com/support/sensors/f/1023/p/749295/2775143#277514

    Thanks and regards,

    CHETHAN KUMAR Y.B.

  • 0 in reply to CHETHAN KUMAR Y.B.
    Expert 1460 points

    Hello Chethan,

    Thank you  very much for clear answer. I understand your explanation. The absolute radiation pattern measurement in the another post is also good reference to me.

    Best Regards,
    Katsuhiro