Re: Confused - transmission line component in Virtuoso and ADS

In my virtuso analoglib there is no cline. Is it possible for you to show me how to use tline for the example I attached.

I have seen this https://designers-guide.org/forum/Ya...num=1231344965 long ago but I felt it is not relevant to my problem because still I am learning how to do matching itself.

?cline? is included in ?rfTlineLib?.
Your purpose does not require ?cline?.

Show me netlist.
I will correct your netlist.

Surely see and understand https://designers-guide.org/forum/Ya...m=1231344965#1

PORT2 (net06 0) port r=75 x=-60 type=dc
PORT0 (net05 0) port type=dc
T6 (0 net06 0 net05) tline z0=75 f=40G nl=.149
T0 (net04 net010 0 net06) tline z0=75 f=40G nl=.126

Shunt Open Stub

PORT2 (net06 0) port r=75 x=-60 type=dc
PORT0 (net05 0) port type=dc
T6 (0 net06 0 net05) tline z0=75 f=40G nl=.149
T0 (0 net010 0 net06) tline z0=75 f=40G nl=.126

PORT2 (net06 0) port r=75 x=-60 type=dc
PORT0 (net05 0) port type=dc
T6 (0 net06 0 net05) tline z0=75 f=40G nl=.149
T0 (0 0 0 net06) tline z0=75 f=40G nl=.126

I did so, but I got 15.22+j30.48, which was same as when the connection was wrong. With ideal components also there is discrepancy , Is it still okay even If I don't get exact 15+j30?

Why don’t you set reference impedance of port0 ?

Even after setting the port0 reference impedance to 50 ohm, I got the same. However, I think that it shouldn't impact the impedance seen into the network.

Right.

What frequency do you apply for evaluation of Zin ?

I am trying to find Zin at 40 Ghz

OK.

>> Zload=75-j*60;
>> Y1=1/Zload+j*tan(2*pi*0.126)/75;
>> S1=(1/Y1-75)/(1/Y1+75);
>> S2=S1*exp(-j*4*pi*0.149);
>> Zin=75*(1+S2)/(1-S2)

Zin =

  15.2275 +30.4832i

by the way, setting something in the port is changing what impedance we see at the input of the network.


For example in this case
https://www.edaboard.com/showthread....74#post1652774

I see Zin as 5.74+j*2.63 ohm when no reference impedance is set in the port and Zin is 5.74+j*5.42 when reference impedance is 5.5+j*2.8. I don't know how it is impacting.

What tool do you use ?
If you use ADS, it can never be even for complex value reference impedance.
However don't believe Cadence Direct Plot in ADE, especially for complex value reference impedance.

Also don't believe Calculator functions in Cadence ViVA.

Instead, use skill function directly.

What tool do you use ?
How to evaluate Zin ?

Cadence

Thanks for the suggestion, so far I just used GUI, maybe I should take advantage of coding.

I keep a port wherever I want to find impedance and run s-parameter simulation. This is the only way I know.

What do you want to mean ?
Use correct terminology.

What do you want to mean ?

What do you want to mean ?

Show me port reference impedance.
Show me Skill or OCEAN code for evaluation of Zin.

Direct Plot in ADE use OCEAN function "zm()".
However it is not valid for complex reference impedance.

Calculate Zin based on correct theory by primitive Skill function without using "zm()".

The followings are general notes for you.

- Always describe correct tool's name and vendor's name which you use as tool or simulator.
- Describe in detail and correctly with using correct terminologies.
- Warnigns are different from Errors.
- ADS is not name of simulator.
- There is no tool which name is Cadence.
- Don't use Direct Plot of Cadence ADE blindly without knowing definition.
- Don't mix up Simulation with Post Processing. They are completely different phase.
- MATLAB are different from Simulink.

Oh ..I plot real and imaginary parts from ZM function in Direct plot, Is it not equal to Complex impedance looking into the port?
Thanks for the guidelines,
1. I know ADS and Cadence are Electronic design systems. You say they are not tools, but I think they are software tools for electronic design. Can you tell me why they are not tools? And what are tools as per you?
2. I know Spectre is a simulator, Virtuoso is Schematic editor.
3. I don't know exactly what is Skill and OCEAN but I think they are CAD scripting languages. But I do know that whatever I do using GUI, it will generate some script in the background. For example, I don't write netlist, however from the schematic I drew in virtuoso, it will be automatically generated for me.

There is no tool whose name is Keysight, Synopsys, Mentor, etc.

ADS is a name of design framework.
Virtuoso is also a name of design framework.

It gives correct value if port impedance is pure real number.
However it never gives correct value, if port impedance is complex number.

See https://www.edaboard.com/showthread.php?378353#8
https://www.edaboard.com/showthread.php?378353#12

Wrong. Cadence is a name of Company.

ADS is a name of design framework.
Virtuoso is also a name of design framework.

See https://www.edaboard.com/showthread.php?354854#10

Needless to say, very wrong.

There is no tool whose name is Keysight, Synopsys, Mentor, etc.

Right.

Wrong.
It is a Design Framework.

Cadence Virtuoso is managed by Skill Language.

OCEAN is a high level function library of Skill.

Cadence ADE is a Launcher of Netlister, Simulator, Postprocessing, etc which generates Skill Code and executes Skill Code.

Netlister, Simulator and Postprocessing are all independent tools each other.
You can choose any vendor's tools except for netlister generally.

So Cadence ADE is none of Simulator and Postprocessing.