I want to use E5071B to characterize a differential saw filter and use the ADS loading the S4P file measured by network analyzer so that I can do the impedance matching for this device. Originally, I save the S4P file without turn on the balun which is in fixture simulator and cannot obtain the same response plotted in datasheet. Then I turn on the balun function saving the S4P file again and use the same ADS simulation setup, the result is very close to the datasheet. I have consult with the FAE in TAIWAN and they say that it should be no difference between these two S4P file and they think the difference I saw before is just because of different sweep time. I don't think so since I have done many try to confirm my operation. If they are different just because of different sweep time, how could the power levels between two S4P files after impedance matching have 10dB difference? Could anybody tell me what's difference between these S4P file?