padpan said:Based on the uploaded results there is a fundamental (possibly wrong) assumption in the ground conditions in the HFSS setup.
L increases significantly and with considerably high slope as it approaches resonance. Qualitatively, those abrupt changes on the way to resonance are usually due to the ground assumptions you have made (or boundary conditions). Theoretically, total absence of a ground reference (this is impossible!) would result in extremely high resonance frequency.
I would suggest re-checking your simulation setup for HFSS.
House_Cat said:Without going through your model in each of the programs, my first reaction is "of course there will be differences".
Each of the software suites uses a different mathematical method to analyze the model. HFSS uses 3D FEM, Sonnet uses FFT-Based analysis, and Agilent's Momentum uses Method of Moments (MoM).
You're comparing different mathematical assumptions, and calculation methods. The only way to verify which one is the closest model for your needs is to actually build a prototype, and compare it with your calculation results.
Use Google and enter - "compare results HFSS momentum sonnet" (without the quotes). You'll get a long list of papers that have been written over the years doing exactly what you are doing - comparing and questioning the results from the various software packages available.
House_Cat said:Each of the software suites uses a different mathematical method to analyze the model. HFSS uses 3D FEM, Sonnet uses FFT-Based analysis, and Agilent's Momentum uses Method of Moments (MoM).
Kaiserh said:Hi all,
Actually I met the same problem in HFSS when I simulate a stacked metal on-chip spiral inductor. The bottom of the silicon is set to PEC ground. Lump ports are used from ground ring (like the one in HFSS inductor tutorial) to inductor. But compare to measurement results, the inductance and Q factor are much larger in HFSS (20% at least). I tried to increase mesh density (by using solve inside, skin depth and increase pass numbers), however the results have really small changes.
All parameters are followed with the "reality" (silicon resistivity, different conductivity for different metal layers and so on). This mismatch problem has bothered me for days. And no good solutions yet...
my question: is the ground ring (PEC in simulation) can affect the inductance and Q of the inductor or not? if it does affect the results, how can I de-embedded it?
Thanks in advance!
Best Regards,
Kai
dingjingfeng said:The example of HFSS is wrong!!!!
in fact HFSS also added the ground ring to in calculation.
then it added a pec line which will increase the inductance and increase the Q
solution:
deleting the ground ring and connect the indcutor port to outer, and using wave port(one side connect to buttom Pec ground)
and comparing the result again!!!
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?