What is wrong with the circuits for QPA1022?

[saulbit]

The circuit is a pa power designed for 4 Watt output power for 9.2GHz~9.3GHz, which is used for a traffic radar.

The circuit consists of two stage of amplifiers, inserted with the isolators. The first is HMC451LP3, and the input power is 0dBm, Continuous wave; then is a isolator designed for 9.2G~9.3G; then is the QPA1022, and the last is the same model of isolator.
According to the datasheet for QPA1002, the input is 12dBm can make a 36dBm output power, and mine is poorly 30dBm, so what is wrong? Am I unlucky to get two broken QPA1002 chips?

 

[vfone]

Assuming you followed the layout, PCB material, and recommended components by Qorvo and ADI, everything should work fine.
These are high gain amplifiers (18dB and 24.5dB), and you don't use any impedance matching components because you use isolators.
Take step by step, check first the DC bias voltages and if they are well decoupled.
At this relative high frequency is not hard to loose 6dB by a simple mistake.

The oscillation without input power, that you mentioned in the Word document, is not normal and should be fixed.
The combined amplifiers should be stable with or without input power, and also should be stable with or without any shield in place.

 

[JohnBG]

Hi saulbit this is JohnBG2021,

would you detail those 2 'isolators'?

can you measure s11 and s21? If so please share the measurements.