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difference in output power measurement

Question asked by nsm on Jun 18, 2012
Latest reply on Jun 26, 2012 by daras

I am trying to characterize the output power of a high power device(peak o/p power 46dBm) using a network analyzer and also a power meter. I am doing the measurements in the pulsed mode.

The output power and the insertion gain is measured at -13dBm.

1. I have done a source power cal and an enhanced response cal for measuring the S21 and the S11 measurements. I get a gain of approx 68dB. The input return loss is at -4dB(very poor).
2.For doing the output power measurements on the DUT , I do a source power cal on the network analyzer at the frequencies I need to measure the output power.
3. I find that there is a difference of more than a dB between the power indicated on the power meter and the o/p power computed from S21-input power.
4. I am using a total attenuation of 40dB in the path. The power meter sees a good match at the output of the device.

Is the difference in the power calculated and measured because of the poor return loss. The DUT is also in compression.

Could you please clarify.