Input impedence to see the effect of Miller effect

[vinanalog]

See the schematic attached. Since the amplifier is having a a negative gain at dc, I am expecting the real part of my input impedance as positive,through miller approximation. But cadence simulation gives a negative value for the real part of input resistance(or it gives a phase of 180 degrees at dc) Wy so?

 

[crutschow]

A single-stage common-source amplifier always has a inverted output (phase of 180 degrees) at DC or low frequencies. That gives a negative (inverted) gain.