The simulation of the following circuit is done in Cadence. The voltage source is a pulse generator with frequency 100Mhz and the blue cross in the schematic match the blue waveform in the simulation result and same for the purple cross and finally the red waveform is the input voltage source. I don't understand why the voltage of the purple node is negative. I understand that capacitor C3 will not allow oppose transient effect, so when it's upper node (blue) increase...same should happen to it's lower node (purple) this means to be positive...so why the purple waveform is negative ?
Your pulse signal begin with 1.1V at time=0.
So DC operation point determination results in such response.
I can know you use Cadence Wavescan as post processing.
But I can not know what simulator you use at all.
We can use Cadence Wavescan for various simulators.
Set "UIC" as Transient Analysis Option, if you use HSPICE.