ueckid
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Hi all,
I am now designing a power amplifier (PA) at 2.4 GHz using microstrip lines as input and output matching networks on a Rogers 4350B substrate. This PA was designed using the harmonic termination technique. Simulation substrate parameters of this substrate are given in its datasheet. Input matching network (IMN) was treated to 2f0 while output matching network (OMN) was treated up to 3f0 using open-circuited stubs. The simulated results were very good based on EM simulation.
However, I am now facing an issue of large differences in impedances between EM simulation and measurements at f0, 2f0 and 3f0 for both IMN and OMN. We measured impedances of the fabricated IMN and OMN using a VNA from Keysight (DC-26.5 GHz) with input power of -30 dBm, IF bandwidth of 20 Hz. VNA was calibrated using a full 2-port mechanical SOLT calibration kit. SMA connector was not de-embedded in the measurement. The differences become more significant at high frequencies range.
As you see in the attached file, magnitude of transmission and reflection coefficients among Schematic, EM and Measurement results are not so deviated. However, the vector impedances on Smith chart among these results are terribly deviated. As you see that Schematic and EM results agree well but the measurement results are deviated. I think that SMA connectors don't play a major role for this deviation.
Attachments are descriptions of my design.
Could anyone suggest solutions for my issue?
Thanks alot in advance!
I am now designing a power amplifier (PA) at 2.4 GHz using microstrip lines as input and output matching networks on a Rogers 4350B substrate. This PA was designed using the harmonic termination technique. Simulation substrate parameters of this substrate are given in its datasheet. Input matching network (IMN) was treated to 2f0 while output matching network (OMN) was treated up to 3f0 using open-circuited stubs. The simulated results were very good based on EM simulation.
However, I am now facing an issue of large differences in impedances between EM simulation and measurements at f0, 2f0 and 3f0 for both IMN and OMN. We measured impedances of the fabricated IMN and OMN using a VNA from Keysight (DC-26.5 GHz) with input power of -30 dBm, IF bandwidth of 20 Hz. VNA was calibrated using a full 2-port mechanical SOLT calibration kit. SMA connector was not de-embedded in the measurement. The differences become more significant at high frequencies range.
As you see in the attached file, magnitude of transmission and reflection coefficients among Schematic, EM and Measurement results are not so deviated. However, the vector impedances on Smith chart among these results are terribly deviated. As you see that Schematic and EM results agree well but the measurement results are deviated. I think that SMA connectors don't play a major role for this deviation.
Attachments are descriptions of my design.
Could anyone suggest solutions for my issue?
Thanks alot in advance!