Fully Distributed Modeling, Analysis and Simulation of an Improved Non-Uniform Traveling Wave Structure

Modeling and simulation of communication circuits at high frequency are important challenges ahead in the design and construction of these circuits. Knowing the fact that the lumped element model is not valid at high frequency, distributed analysis is presented based on active and passive transmission lines theory. In this paper, a lossy transmission line model of traveling wave switch (TWSW) is presented and fully distributed analysis of this structure is also introduced. In the off state, the ordinary single pole single throw (SPST) switches operate as short or open circuit and return an observable part of the signal. To improve return loss in the off state, a non-uniform structure of SPST switches is proposed which is based on the artificial tapered transmission line produced by applying various controlling voltage at the gate. The analysis of ordinary and improved structure of SPST switches is performed and it is further compared with that of the semi-distributed and fully distributed methods. The results of simulation easily approve the improvement of matching in the off state.