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PNA-X High Power IMD Power sweep measurements

Question asked by rok on Jan 9, 2019
Latest reply on Mar 6, 2019 by Dr_joel



I am using  a N5245A 50GHz PNA-X with options 400, 419, and 423. My company wants to test a high power amplifier using IMD measurement channel with each of the 2 input tones set to as high as 25dBm (at the output of a low-loss coaxial cable connected to Port 1) around the 20+GHz frequency range in a power swept sweeping condition. From this weblink: High Power PNA-X , it shows a diagram where you connect a booster amp (shown in purple) to rear connectors J11 and J10. So if I need 2 input tones with amplitude levels as high as 25dBm, do I connect another booster amp to rear connectors J8 and J9? If so, what is the characteristics of the internal combiner inside this particular model of PNA-X (in terms of damage levels, insertion loss, and coupling factor)? Or to pose the question another way, what is the minimum spec of the secondary booster amp for the 2nd input tone to achieve the desired 25dBm level, since it probably needs to have a higher capability versus the first booster amp? 


Or is there another way, such as putting the booster amp at the front, after Port 1 on the PNA-X, such that we generate the 2 combined tones from the PNA-X and then feed that into the booster amp, as described in the ENA version of your high power amplifier measurement document at:  on page 5, figure 3, but with the drawback of not being able to take good S11 measurements due to the reverse isolation of the booster amp?