Simulating Inductor SRF using Lumped Elements

[chiques]

I see that the equation to determine SRF of a capacitor or inductor is:

https://www.coilcraft.com/getmedia/8ef1bd18-d092-40e8-a3c8-929bec6adfc9/doc363_measuringsrf.pdf

But when I follow this simulated circuit shown on https://www.microwaves101.com/encyclopedias/self-resonant-frequency , the equation is the following for an inductor.

I see they mentioned they added a factor of 1000 so the equation works out. What I don’t understand is why the equation is way off from the SRF version.

Note: The Microwaves simulation in my simulator is close but still off. I get 1.7GHz SRF where they get 2.3GHz.

When I try to correct the simulation to

I get:

Anyone have any idea what I’m missing here?

 

[FvM]

Are you assuming that any RF inductor has a parallel capacitance of 1 pF? It's just a typical value used in the microwaves article. Has to be replaced by an actual value for your inductor. Also ESR may be different.

 

[albbg]

I think it's just a typo: in the article (of microwave101) they wrote pi*2 instead of pi^2 and SRF*2 instead of SRF^2. The factor 1000 is used only to convert between measurement units.

 

[vfone]

I don't know from where are the 1.7GHz and 2.3GHz results.
51nH in parallel to 0.2pF resonates on 1.576GHz.

 

[chiques]

I think it's just a typo: in the article (of microwave101) they wrote pi*2 instead of pi^2 and SRF*2 instead of SRF^2. The factor 1000 is used only to convert between measurement units.

This is confusing because if I correct their typo's, the circuit does not simulate :/

 

[FvM]

"Does not simulate" means?

 

[chiques]

"Does not simulate" means?

The simulation does not resonate at the desired frequency.