I am supposed to compare the measured S parameter data and the simulated S parameter for a discrete LDMOS power transistor package which has 2 die in it.
Based on the previous experience I know there will be some deviations between both the results as it's always obvious. But in this case I see oscillation only at a particular frequency in the measured data. I ran all stability analysis in the simulation and it did not even show tiny variation. So I am confused as to how to go about this. Thanks
Unstability may come from the implementation of the board.connectors.vias etc.The measured s-parameters are generally measured on basic 50 Ohm input/output PCB and any practical implementation with biaising,matching,filtering,decoupling etc. may induce some unstability problems.
Oh yes. But how to verify it's the board which caused the oscillations? Or Is there some factors affecting the whole circuit due to which I cannot see it in the simulation ?