Many times, after a thorough and, some times, exhausting design process staring the simulator in the computer, it happens that the results obtained in the laboratory from the first bread boards manufactured are rather far from the theoretical analysis.
Almost of all the times, this miscorrelation of the results compared to the simulations are due to lack of accuracy in the models used.
One of the most significant details normally underestimated by the designers is the effect of connectors used for testing the PCBs.
SMA connectors are one of the most used connectors type in RF designs, because of the quality and its, general speaking, low cost.
But they are not transparent to the actual measurements once the are introduced in the testing PCB.
The effect is clear, even when the most simple structures are remarkable. In the present document it is presented a simple method to obtain the electrical model for SMA connectors that can improve the results of the circuits design.
Extracting the lumped elements model for the SMA connector in QUCS Studio
