Cluny
Junior Member level 1
doherty amplifier + 2009
I have to design a full integrated doherty power amplifier at 5GHz. After designing the carrier in Class AB and the peak in Class C I tried to connect each other at the outputs (the inputs are still not connected)... but I'm not able to get the same current-phases for a constructive addition at the combining-node: There's everytime a difference of nearly 180 degrees, irrespective which phase-offset at the peak input is chosen.
I believe that I understand the doherty-technique and the related configuration... that means I've choosen the correct impedance inverter (ZT = 2*Rload) etc...
I tried a lot of things to solve the problem... but until now it does not work : (
May someone knows what the main impact on this phase-shift-problem...
I have to design a full integrated doherty power amplifier at 5GHz. After designing the carrier in Class AB and the peak in Class C I tried to connect each other at the outputs (the inputs are still not connected)... but I'm not able to get the same current-phases for a constructive addition at the combining-node: There's everytime a difference of nearly 180 degrees, irrespective which phase-offset at the peak input is chosen.
I believe that I understand the doherty-technique and the related configuration... that means I've choosen the correct impedance inverter (ZT = 2*Rload) etc...
I tried a lot of things to solve the problem... but until now it does not work : (
May someone knows what the main impact on this phase-shift-problem...