"RST Engineering \(jw\)" writes:

Agreed, John, 150 MHz is damned near DC for a lot of us, but as yet I have
no answer from the "spice" folks for the 1 nf capacitor question. A lot of
fancydancing but no answers.

I am not an expert, but can you not just add a bit of series L to
approximate this? Or even transmission line for higher frequencies /
longer tracks.

I have had surprisingly good results simulating a single transistor
UHF oscillator at ~500MHz. The results agreed with reality quite well,
even *without* explicitly modelling all the parasitics. Certainly
spice was better than me at predicting what would happen (although
that is not saying much!) I guess perhaps the reason that I could get
away with this was because of the small size and high performance of
SMT parts these days.

--

John Devereux