Dear friends,
I want to design LNA.I want to estimate the via effect of the source to GND.I use the FR4(1mm sub,35um cond) and via(pad diameter=0.7mm,drill size diameter=0.4mm),i simulation by ADS,and get the value L=447.6pH,when i meaure the via,i only get L=1.0886nH.
Now i attach my simulation and measured result,any friend can tell me the root cause?
44 nh is at least a factor of 10 too big for the via hole inductance. I would look closely at the via hole input numbers, and see if you have made an entry error.
A via hole is not modeled fully by just an inductance to ground, there are stray capacitances, some line length, etc. too.
Thanks and sorry that i made a mistake.Now i correct it.It is inaccurate .
Added after 21 minutes:
biff44 said:
44 nh is at least a factor of 10 too big for the via hole inductance. I would look closely at the via hole input numbers, and see if you have made an entry error.
A via hole is not modeled fully by just an inductance to ground, there are stray capacitances, some line length, etc. too.