As before, a preliminary analysis based on the simple series L-C model is used for each capacitor.
The L-C model simulation indicates the resonance to occur very near to the frequency arrived at from the preliminary analysis (8.9 versus 8.4 GHz).
Simplified L-C models, which might closely emulate measurement data from a series two-port test fixture, often prove to be inaccurate when used in common circuit configurations.
The true advantage of the triplet topology as applied to the L-C filters is the ability to substitute a transmission line resonator in place of the L-C resonator within the triplet.
For use in a filter, the stub must be as accurate a substitute for the L-C network as can be conveniently realized.
Once the procedures are in place to adjust the impedance at the top of the resonator and accurately replace the L-C network with a shorted stub, iterations can be used to force any values of L, C or stub impedance needed as a totally independent step after all other transformations are complete.