How are time delays handled in control system design?

Time delays (dead time) add phase lag without affecting magnitude: G_delay(s) = e^(-Ls). This reduces phase margin and limits achievable bandwidth. Handling approaches include: Pade approximation (rational approximation of delay for analysis), Smith predictor (model-based compensation that effectively moves delay outside the loop), delay reduction (increase sampling rate, reduce transport lag), and conservative tuning (accept slower response). Significant delay relative to time constants severely limits achievable performance.