Interdigitated Electrode Capacitor

[hassan.mahmoud]

I am trying to simulate interdigitated capacitor in HFSS to calculate the capacitance over frequrncy what the best way to excite the structure.

 

[D.A.(Tony)Stewart]

Bode plot or swept CC impedance plot or Smith Chart

Can you improve on these specs?

 

[hassan.mahmoud]

I am trying to simulate interdigitated capacitor in HFSS to calculate the capacitance at different frequencies. But the results are not correct, I tried first with maxwell with DC voltage and when compared the results at low frequencies from HFSS they are not the same. I attached the model if anyone can help.

 

[BigBoss]

I'm new to HFSS ( trying to learn ) but Modal Network is fine for this type of Planar Devices.
HFSS Hybrid and Arrays solution type is also used in different type planar problems.

--- Updated Dec 27, 2023 ---

I have used HFSS Modal Solution and found this Z₁₁ ( Source is Circuit Port )

That's equivalent to 4.2pF@20MHz.

 

[D.A.(Tony)Stewart]

each path has inductance/mm and pF/mm so many resonant frequencies when unloaded.

https://www.researchgate.net/profile/Jules-Hammond/post/How-do-I-calculate-the-capacitance-of-an-Interdigital-capacitor/attachment/59d61e9979197b807797d038/AS%3A279381495828485%401443621147143/download/Novel+Planar+Interdigital+Sensors.pdf?_tp=eyJjb250ZXh0Ijp7ImZpcnN0UGFnZSI6InF1ZXN0aW9uIiwicGFnZSI6InF1ZXN0aW9uIiwicG9zaXRpb24iOiJwYWdlQ29udGVudCJ9fQ

I think Ck = Dk A/h where A= length * width over height to ground plane but I usually just use calculator on PCB Toolkit

 

[hassan.mahmoud]

I'm new to HFSS ( trying to learn ) but Modal Network is fine for this type of Planar Devices.
HFSS Hybrid and Arrays solution type is also used in different type planar problems.

--- Updated Dec 27, 2023 ---

I have used HFSS Modal Solution and found this Z₁₁ ( Source is Circuit Port )
View attachment 187339
That's equivalent to 4.2pF@20MHz.

Thanks to the response
Can you uploaded the model you used, I wanted to see how you solved it?

 

[BigBoss]

As I have said before, I'm newbie to HFSS and I dont' want you to mislead.
You can verify/compare this result by theoretical calculation.

 

[D.A.(Tony)Stewart]

If you have any problem, detail the steps you took to create it, so we can determine where you went wrong to go where you want.