Need help for load pull analysis of PA using ADS2022

narayani · Jul 25, 2023

I want to do Load Pull Analysis of MMIC Power Amplifier. I have listened Anuragh Bhargav's RF Design-13: Getting Started with Load Pull Simulations (Link for the same is attached below). After listining the same I started designing PA using Keysight Technologies ADS 2022 by following the steps from the same RF Design Tutorial -13 and I followed exactly. When I simulated Load Pull Analysis, I am getting blank graphs. Someone can guide me how to plot load pull analysis. Below I have attached the screen shots which I have taken from RF Design-13 and obtained results.

Desired Outputs graphs are as follows:
1. Desired_Ouput_Graphs
2. Desired_Ouput_Graphs_1
3. Desired_Ouput_Graphs_2
4. Desired_Ouput_Graphs_3
5. Schematic_1
Obtained Outputs are as follows:
1. Schematic_Drawn_Using_ADS2022
2. Obtaind_Output_Graphs

BigBoss · Jul 25, 2023

Any error message ?? Check the datasets' names.There are multiple simulation controller and each one may create a particular name.
You can also use "Load Pull Design Guide" instead of this, there are many Templates and Test Benches to be used.

volker@muehlhaus · Jul 26, 2023

One difference: in the PAE instance, the tutorial schematic defines PAE, but you defined PAE1.

narayani · Jul 27, 2023

volker@muehlhaus said:
One difference: in the PAE instance, the tutorial schematic defines PAE, but you defined PAE1.View attachment 184032

I have changed PAE option as you rightly pointed out. But there is no change in the output graph. I have attached the same below.

--- Updated Jul 27, 2023 ---

narayani said:
I have changed PAE option as you rightly pointed out. But there is no change in the output graph. I have attached the same below.

I am trying also using Load Pull Deign template.

volker@muehlhaus · Jul 27, 2023

There is no magic solution, you need to troubleshoot this step by step.

If you click on the red equation (=error) in ADS data display, you will see a message what each problem is. It might be something simple as a typo.

narayani · Jul 31, 2023

volker@muehlhaus said:
There is no magic solution, you need to troubleshoot this step by step.

If you click on the red equation (=error) in ADS data display, you will see a message what each problem is. It might be something simple as a typo.

I am getting output power when we use load pull analysis template. I have some doubts. In the template, they have shown only single frequency (RF_Freq= 1000 MHz). My doubt is how to sweep the values from 2 to 4 GHz and get output power from the same. Because I want to design PA from 2 to 4 GHz and get the output power for the same range.
One more doubt is can we use entire circuit with input and output matching circuit or simply use transistor to get the output power and PAE. Is it enough.
Below I have attached the Load Pul Anslysis from ADS Cook.

BigBoss · Aug 1, 2023

narayani said:
I am getting output power when we use load pull analysis template. I have some doubts. In the template, they have shown only single frequency (RF_Freq= 1000 MHz). My doubt is how to sweep the values from 2 to 4 GHz and get output power from the same. Because I want to design PA from 2 to 4 GHz and get the output power for the same range.
One more doubt is can we use entire circuit with input and output matching circuit or simply use transistor to get the output power and PAE. Is it enough.
Below I have attached the Load Pul Anslysis from ADS Cook.

It's a little bit tough task. Optimum Load Impedance along this band will NOT be same for Constant Power. They might be closer even very close but not same. You have to choose an appropriate and compromised point to get "almost" same power level.
This statement is also valid for Input Matching Circuit. There won't-possibly- be an unique circuit but closer matching circuit.

narayani · Aug 2, 2023

BigBoss said:
This statement is also valid for Input Matching Circuit. There won't-possibly- be an unique circuit but closer matching circuit.

Can't we have exact input matching and output matching circuit at the input and output of PA respectively whatever we are using at the input and output matching circuit for simulation purpose.
I have few doubts in the Load Pull Instrument simulation. I have attached below Load_Pull_Instrument_1 and Load_Pull_Instrument_2 screen shots.
1. In Load_Pull_Instrument_1 screen shot, I have shown some parameters such as S_imag_min = -0.3, S_imag_max = 0.4, etc. How to set values to these parameters or let it be as it is default values and what do you mean by these parameters.
2. In Load_Pull_Instrument_2 screen shot, I have shown some parameters in the Square and Round box. How to set values to these parameters or let it be as it is default values and what do you mean by these parameters.
I am getting confused by observing these parameters. Please clarify these doubts.

BigBoss · Aug 2, 2023

narayani said:
Can't we have exact input matching and output matching circuit at the input and output of PA respectively whatever we are using at the input and output matching circuit for simulation purpose.
I have few doubts in the Load Pull Instrument simulation. I have attached below Load_Pull_Instrument_1 and Load_Pull_Instrument_2 screen shots.
1. In Load_Pull_Instrument_1 screen shot, I have shown some parameters such as S_imag_min = -0.3, S_imag_max = 0.4, etc. How to set values to these parameters or let it be as it is default values and what do you mean by these parameters.
2. In Load_Pull_Instrument_2 screen shot, I have shown some parameters in the Square and Round box. How to set values to these parameters or let it be as it is default values and what do you mean by these parameters.
I am getting confused by observing these parameters. Please clarify these doubts.

They are variables which are used in equations page.
These limits restrict the sweeping and they can be easily modified in regard of your purpose.
For instance you can sweep whole Smith Chart at the beginning to find coarsely optimum values then shrink the region by restrict the limits to find precisely the optimum value.
That's the purpose.

narayani · Aug 2, 2023

Sorry for trouble. I have tried to get good Output Power and PAE for higher frequency at 27 GHz using 0.15um GaN HEMT transistor. When I did load pull analysis in this frequency. I am getting too low Output Power and Power Added Analysis (PAE) (Which graphs I have attached below).
What should be done to get Output Power and Power Added Efficiency (PAE) more than 5 Watts and 35 %.

BigBoss · Aug 2, 2023

Didi you see the Power Gain @ max. Power or max. PAE ??
Gp=0.3 dB !!
Something is not going on well my friend. Work on optimization ..

Hint: Sweep the Load along whole Smith Chart coarsely/roughly then find a good region that satisfies you then shrink this region by changing the equation limits that we have already talked about.( Center, max. real and imag. parts )
After that make additional Load Pull simulation with finer steps.

narayani · Aug 5, 2023

I am getting error during parameter sweeping Load Pull Simulation. I have included parameter sweep varaibles and swept variables though I changed SweepVar in both Load Pull and Load Pull Instrument analysis. How to remove this error. Guide me. I have attached error messages below.

narayani · Aug 10, 2023

narayani said:
I am getting error during parameter sweeping Load Pull Simulation. I have included parameter sweep varaibles and swept variables though I changed SweepVar in both Load Pull and Load Pull Instrument analysis. How to remove this error. Guide me. I have attached error messages below.

Some can help me to remove this error.

BigBoss · Aug 10, 2023

SweepVar must have a default value. Also it might be a Internal ADS Variable (not sure)
Simply ;
Assign a Default Value for variable frequency like that.

LoadPullFrequency=26e9

RF_Freq=LoadPullFrequency in X1 (without unit)
Start=26e9 and Stop=32e9 and Step=500e6 in Sweep1

narayani · Aug 13, 2023

BigBoss said:
SweepVar must have a default value. Also it might be a Internal ADS Variable (not sure)
Simply ;
Assign a Default Value for variable frequency like that.

LoadPullFrequency=26e9

RF_Freq=LoadPullFrequency in X1 (without unit)
Start=26e9 and Stop=32e9 and Step=500e6 in Sweep1

As you said, I made changes. I am getting same error as before how I was getting. I tried all options, I could not eliminate errors. Guide me someone, how to overcome this difficulty. I have also attached below relevant schematic screen shots.

BigBoss · Aug 13, 2023

Perhaps you have to copy VAR1 on the top level into Load_Pull_Instrument1 level. It might not see the VAR1.

narayani · Aug 13, 2023

BigBoss said:
Perhaps you have to copy VAR1 on the top level into Load_Pull_Instrument1 level. It might not see the VAR1.

After including VAR1 in the top level also, I am once again getting error.

narayani · Aug 13, 2023

I am getting one more trouble while simulating Constant Power Delivered Load Pull. When I press execution button , execution is not at all terminating immediately. It keeps executing and it is taking more than 2 hour and also will not come out of the execution.
Guide me how to come out of the execution after few minutes. If I stop the execution at the middle, it is not showing any output and it is showing blank output.

Need help for load pull analysis of PA using ADS2022

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