Real-valued discrete-time impulse response representation of bandpass S-parameters

Accurate and efficient time-domain simulation techniques for broadband microwave networks at system level are highly desirable in modern computer-aided-design (CAD) tools, because of advantages in terms of high simulation speed and the reduced requirement for full circuit-level details of the simulated networks. A method for accurate time-domain representation of bandpass S-parameters is proposed in this paper, in order to produce fast time-domain steady-state responses of broadband high-frequency linear, time-invariant systems. A real-valued discrete-time impulse response (DTIR) representation is used in the proposed method. As a result, the processes of down-conversion and up-conversion of input signals and system bandpass transfer functions normally required in bandpass analysis, can be effectively avoided. For example, the method can be used in the design of distortion cancellation circuits in full-duplex communication systems.