A Mixed Time-Frequency RF Simulation Technique Based on Numerical Time-Slot Partitioning

Abstract:
The increasing complexity of radio frequency (RF) architectures and the continuous push to profit from digital signal-processing techniques, have been addressing new challenges to circuit-level simulation. This paper describes the most relevant details of a time-frequency simulation technique specially conceived for the efficient numerical simulation of circuits whose stimuli are turned on and off for unknown periods of time, as is the case of RF circuits managing signals coded in some on-off digital scheme. The proposed technique is based on a time-slot partition stratagem with automatic switching between different numerical schemes (multitime envelope transient harmonic balance and time-step integration) along the simulation process, according to the onoff state of the circuits’ stimuli. Simulation tests performed in an illustrative application example, an on-off amplitude shift keying (ASK/OOK) transmitter used in low-power applications, as radio frequency identification (RFID) or biomedical imaging, revealed significant gains in computational speed over commercial computer-aided design tools.