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EM simulation on ADS of simple CPW structure

ab_basu

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Hi,

I am new to simulation in ADS, and I want to do EM simulation of a basic CPW structure. I need a step-by-step guide to do so. I used line calculation to optimize Lwisth and length. I have attached the circuit and basic S-parameter of the design (Fig. 1 and 2). Then I generate a layout, that came like Fig. 3. What to do after this? I tried to use substrate as a Si substrate with 1 mm thickness. But I think I am doing something wrong. Please I need it urgently. Somebody, please help.
 

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vfone

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The line dimensions and substrate information of the CPW transmission line that you set are not meaningful.
Use a transmission line calculator before doing these settings.
Try using the settings in the example I attach.
 

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volker@muehlhaus

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But I think I am doing something wrong.

Yes indeed!

As you can see in layout, there is no side ground created. Layout just draws a zero width line to indicate where side ground edge starts. The second issue is that not only the side ground is missing, the ground pins are missing as well. So your simulated structure is a microstrip line, with ground return at the bottom of the substrate.

You can use my application note on parameterized layout for EM in ADS:
but CPW is a bit tricky.

If you do NOT need to include metal thickness, and zero width EM solution is good enough, you can use the lot mode in Momentum where you draw the SLOT instead of the conductor. Then you could use (abuse) the MCLIN microstrip model to generate the layout (representing the CPW slot!).

There should be some instructions in ADS online help on CPW simulation using the slot mode.

Good luck!
Volker
 

ab_basu

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Yes indeed!

As you can see in layout, there is no side ground created. Layout just draws a zero width line to indicate where side ground edge starts. The second issue is that not only the side ground is missing, the ground pins are missing as well. So your simulated structure is a microstrip line, with ground return at the bottom of the substrate.

You can use my application note on parameterized layout for EM in ADS:
but CPW is a bit tricky.

If you do NOT need to include metal thickness, and zero width EM solution is good enough, you can use the lot mode in Momentum where you draw the SLOT instead of the conductor. Then you could use (abuse) the MCLIN microstrip model to generate the layout (representing the CPW slot!).

There should be some instructions in ADS online help on CPW simulation using the slot mode.

Good luck!
Volker
Thank you for your help and sorry for the late reply.
Sorry, I did not get your point. Why the side grounds are not created?

I need to simulate the CPW with the dimensions measured from Line Cal. Please guide me step by step.
I want to
 

volker@muehlhaus

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ADS auto-generated layout does not draw side ground AREA because that can be large or small, depending on other elements in your layout. Only the distance to the side ground is cleary defined. So you must add metal manually in ADS layout.

There are some nice "Learn ADS in 5 minutes" tutorials in youtube, if you are interested to learn about ADS layout.
 

ab_basu

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ADS auto-generated layout does not draw side ground AREA because that can be large or small, depending on other elements in your layout. Only the distance to the side ground is cleary defined. So you must add metal manually in ADS layout.

There are some nice "Learn ADS in 5 minutes" tutorials in youtube, if you are interested to learn about ADS layout.
Sir,

Thank you so much for your suggestion. I will try it and get back to you.
 

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