Time-domain techniques in microwave circuit simulation

Microwave circuit simulation has always posed particular difficulties especially in highly non-linear applications because of the presence of distributed or electromagnetic structures, which are usually passive and linear, but difficult to incorporate effectively in time-domain analysis. A variety of specialised techniques has evolved to cope with this situation with reasonable success. In recent years, microwave systems are becoming more integrated and complex and often involve `mixed-signals´ that may operate over a very wide range of time scales, creating new simulation challenges. This study reviews the issues involved and suggests a practical paradigm for generalised time-domain simulation of microwave circuits.