Dear community, I`ve been doing Harmonic Balance simulations with Agilent ADS on a circuit with many inputs in which every input signal goes through a 5 dB attenuator (1tone/attenuator). In the schematic this attenuator is a 2 Port Data Item which has uploaded S-Parameters from the minicircuits site; if you`re interested, the model`s name is PAT-5.
The input power for every tone is 10.37dBm, and the output should be 5.3;
The problem is that the output doesn`t seem to have decreased 5 dB, but some value from 3.3dB to 4.7dB (it changes according to the signal "branch"). This is strange, and at first I supposed that it was related to the vendor`s fault. But then I`ve controlled the S21 and S12 parameters` magnitude, and I found out that it was perfectly -5dB for all the fruencies, which is the correct value;
may this be the S12 and S21`s phase`s fault? I remember that only the magnitude is important for the power, right?
I would like to know if I`m forgetting something, or using the Data Items in a wrong way.
p.s. All the "branches" are matched with the same devices: before the attenuator there is the matched signal generator, and after therere is a matched mixer.
p.s. 2: maybe I`ve found out the reason of this '''non ideality": the input signal`s bandwidth is between 0 and 15.6MHz, while the S2P files starts with f=40MHz (and there is no value for lower frequencies, even though the real components should have f=0MHz). I would like to know how did the simulator see this and why did it behave differently between the various signals.