Arbitrary load in ADS

Help needed to create an arbitrary load in ADS that has a reflection coefficient magnitude =1, so I can sweep the phase.

In other words, the normalized load is on the rim of the unit Smith chart.

Thank you!

Use "S1P_Eqn", "Z1P_Eqn" or "Y1P_Eqn" with equation describing impedance you want.
S1P Eqn to S6P Eqn (1- to 6-Port S-parameters, Equation-Based) - ADS 2009 -*Agilent EEsof Documentation Center
Z1P Eqn to Z6P Eqn (1- to 6-Port Z-parameters, Equation-Based) - ADS 2009 -*Agilent EEsof Documentation Center
Y1P Eqn to Y6P Eqn (1- to 6-Port Y-parameters, Equation-Based) - ADS 2009 -*Agilent EEsof Documentation Center

If you never run transient analysis, you can use "Term" with equation describing impedance you want instead of "S1P_Eqn", "Z1P_Eqn" or "Y1P_Eqn".
Term (Port Impedance for S-parameters) - ADS 2009 - Agilent EEsof Documentation Center

For example,
if you use "Z1P_Eqn" or "Term", set Z[1,1] or Z like following.
Gamma=polar(rho, phase_deg)
Z0=50
Z[1,1]=Z0*(1+Gamma)/(1-Gamma)

if you use "S1P_Eqn", set S[1,1]=polar(rho, phase_deg) and Z[1]=50.

Thank you Pancho for the wonderful tips. It is indeed very helpful.

For Z1P_Eqn, I have to sweep from a small non-zero value to a number slightly less than 360 to get around the "divide by zero" error.

It is very natural since you set rho=1.0.

Why don't you use "S1P_Eqn" ?

BTW, if you use "S1P_Eqn" or "Z1P_Eqn" in Transient Analysis, you have to pay attention to a causality of your impedance expression.
See The Designer's Guide Community Forum - usage *of "port" from analogLib

I did try all the options you suggested.

The impedance causality is very interesting...Do you have more background or basic info on the causality?

See "Dealing with Noncausal Frequency Responses" in Troubleshooting a Transient-Convolution Simulation - ADS 2009 - Agilent EEsof Documentation Center

Thank you so much for the very cool stuff, Pancho! learned something new today.

Hi I suggest follow this link:

http://www.vhdl.org/pub/ibis/connect...one_spec11.pdf

Have a nice day

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