LandLack
Member level 3
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.
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.
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