Cadence virtuoso differential port

[Youssef_Hassan]

Hi all,

I want to use single port for differential feeding in cadence virtuoso, i tried to connect it as in the picture

and i assumed that RF+ and RF- will be differential but when i did transient analysis they appeared in phase and not differential. So what am i getting wrong??
and why doesn't it work as ADS

 

[dick_freebird]

There is no ground reference, so any results will
be questionable. For convenience I would replace
the "PORT0" voltage source with a pair in series of
half amplitude (and half series resistance, if the
symbol is to be believed), and a gnd! attached to
their center tap. Then you should have a differential
ground-referred source.

 

[Youssef_Hassan]

Thank you but even if there is no gorund reference shouldn't the 2pins appear 180 out of phase ?

 

[dick_freebird]

"Should" does not always lead to "did"....

There could be a small out-of-phase difference
riding on top of a gross offset or perturbation due
to there being no capacitance or conductance to
the "reference plane", to absorb minuscule
numerical residue / "noise". Zero divided by zero
= ??? (especially when zero is not exactly zero
and you don't know what).

But it's just my hypothesis at this point; try and
see?