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AWR1843AOP: Why is the Tx EIRP and Noise Figure different for 1843Boost vs 1843AOP

Arindam Sengupta
Prodigy 40 points
Part Number: AWR1843AOP
Other Parts Discussed in Thread: AWR1843, , AWR1843BOOST

Hi,

We have been trying to do a link-budget comparing the 1843 to the 1843AOP and noticed that

A) The transmit power between the two have a 6dB delta [1843Boost = 10dbm vs AOP = 16dbm]

B) The noise figure with the AOP is ~6dB lower than the 1843boost

Could anyone help clarify what is different between the two boards (from an RF standpoint) that is driving these differences?   

  • 0
    TI__Mastermind 35835 points

    Hello Arindam,

    Let me assign this to the right person.

    Regards,
    Saswat Kumar

  • 0
    TI__Mastermind 30715 points

    Hello,

    These measurements do not match expectations.

    The die between AWR1843 and AWR1843AoP is identical, the only difference is the antenna. 

    The AWR1843BOOST has a higher gain antenna so it should have a higher EIRP. We expect around 22dBm EIRP and have seen this to be the case in measurements. The AoP is around 16dBm which matches your measurement. 

    Noise figure cannot be accurately measured on the EVM so I am not sure how you are ending up with your noise figure numbers. 

    Regards,

    Adrian 

  • 0 in reply to aozer
    Prodigy 40 points

    I was going by the numbers from the datasheet:

    1843 datasheet:   

    1843AOP datasheet: 

  • +1 in reply to Arindam Sengupta
    TI__Mastermind 30715 points

    Ok, I understand now. I thought you had measured 10dBm of EIRP on the AWR1843BOOST.

    The AWR1843BOOST uses a PCB patch antenna with ~10dBi of gain. So if we assume 12dBm of power at the ball + 10dBi of gain, this results in ~22dBm EIRP for the AWR1843BOOST. With non-AoP device the overall EIRP of the system will be dependent on the gain of your antenna design, 12dBm is only the power of the TX at the ball. 

    The AWR1843AoP utilizes a small single patch antenna on the top of the package. This antenna + the output power of the transmitter results in an EIRP of 16dBm. 

    Similarly, the noise figure specified in the AWR1843 datasheet is at the device RX pin and the total system noise figure will be dependent on the antenna design. However, the noise figure specified in the AWR1843AoP is very similar to transmitter's effective isotropic radiated power (EIRP) where Tx output power + Antenna gain - Losses are considered. In the similar way for the receiver's Receiver Noise figure + antenna gain -losses are considered for the effective isotropic noise figure. These numbers could be directly used in the link budget calculations. 

    Regards,

    Adrian