TopFinder: a new and efficient tool for topology construction and parameter extraction for RF/merowave transistors

In this paper. a new tool for efficient topology construction of RFMcrowave transistors is proposed. This tool, called TopFinder (from Topology Finder), is able to determine the most appropriate RFMcrowave transistor topology as well as to extract the component values of this topology accurately. Starting from a set of S-parameter measurements as inputs, the tool constructs the optimum topology that best fits this set. The fmal obtained topology could be, in some cases, a simple variation of the widely used basic topology, known as the standard small-signal electrical equivalent circuit transistor topology. However, in most cases, the tool is able to produce an optimum equivalent circuit topology that is significantly different from the standard one. To demonstrate the effectiveness of the tool, we present two examples. In the fmt example, synthetic S-parameter data is generated from a previously know transistor topology and component values. The topology used in this example is slightly different from the standard one (simple variation). In the second example, actual transistor measurement data in the frequency range from 1 to 30 GHz is used. In this case the results show that the final topology fits well (up to 1 %) the measurement data. The produced topology is shown to he significantly different from the standard topology.