According to the concept of displacement current, time varying electric fields give rise to displacement currents. But in a capacitor, once steady current flows, there is no change in electric field. Now how does the displacement current flow? If it does not, it leads to a contradiction. Someone please answer me. Thank you very much.
Your problem is that you're confusing current with charge. In a capacitor the electric field is constant when the current flowing through it is zero. There may be currents flowing through other parts of the circuit in steady state, but the steady state capacitor has charge and no current flow.