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S parameters -Transmission line phase shift

Question asked by Leyo on Dec 17, 2014
Latest reply on Dec 22, 2014 by Leyo
For Power amplifier design, need to figure out exact phase shift  by the Output matching network. For some reason, simulation results are not matching with measured numbers. To understand my mistake, analyzing a simple example.

A transmission line having an impedance of 7.2 ohms and electrical length 59.1 degrees (Freq 1843 MHz, dielectric constant 3.6 ) or 0.164 lamda converts 50 ohms to 1.4-j4.2 ohms. As shown in the attached (ADS_Simulation.jpg), inserted this 7.2 ohms line between two S parameter ports. As shown in the simulation results (Attached figure ADS_Results.jpg) S21 phase is not 59.1 degrees at 1843 MHz. Simulator is showing it as 85 degrees. Tried port 1 impedance as 50 ohms and 1.4+j4.2 (Conjugate of the 50 transformation by the 7.2 ohm transmission line), but results are same. Why I am not getting S21 phase as 59.1 degrees at 1843 MHz?
Appreciate your help.  

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