Gain difference in ADAR1000 evaluation board data sheet and our measurements

We have evaluation board of ADAR1000. The peak measured gain of transmitter and receiver is 21dB and 11dB respectively given in data sheet on nominal bias settings. when we tested it we found the gain 17-18dB and 5-6dB on TX and RX respectively on nominal bias setting.
Testing setup is through the Vector Network analyzer by connecting one port to RFIO point and other with respective TX/RX port and measure its S21 or S12. The return loss is fie but the gain is less than the measured gain in data sheet.

kindly help me to find why there is difference in gain?

                

Measured gain on our systems (TX)                                           Measured Gain in data sheet of ADAR1000 Evalz            Measured Gain on our system (RX)

Parents
  • +1
    •  Analog Employees 
    on May 4, 2021 2:39 PM

    Have you de-embeded the board loss?  If not, that will be 3 - 4 dBs of gain you can add into your measurements (loss changes over frequency). 

    Also, how did you set the part up to get these measurements?  You said nominal bias, but what are the VGA and vector modulator settings? 

    Is this low gain consistent across all the channels? 

Reply
  • +1
    •  Analog Employees 
    on May 4, 2021 2:39 PM

    Have you de-embeded the board loss?  If not, that will be 3 - 4 dBs of gain you can add into your measurements (loss changes over frequency). 

    Also, how did you set the part up to get these measurements?  You said nominal bias, but what are the VGA and vector modulator settings? 

    Is this low gain consistent across all the channels? 

Children