Comments On "Electromagnetic Analysis For Microwave FET Modeling"

The commentor states that the concept of EM-based microwave field-effect transistor (FET) modeling, as outlined in the above-named letter, is not new and has been published before. A first version was published by Jansen (1989) and includes measurement results and implementation into the commercial LINMIC+ software version 2.0, Oct. 1987. The agreement between measured and predicted FET data given there is excellent. The method of analysis, particularly the "localized access," has been used in that paper. More details, including the localized access approach (not using the same name), have been published by the same author. Finally, even a nonlinear version of the EM analysis for microwave FET modeling has been published already by the same group. References for the above are provided. It is the commentor's view that the only difference between the above-named work is that it uses finite-element modeling (FEM) analysis instead of other EM methods for the distributed passive part of the FET/HEMT. In replying, the original authors note the methodology applied in their letter for the modeling of a FET is actually well known, and, moreover, they have not asserted that they were the first to have developed such a solution. Also, the approach used in the original letter differs from those of Jansen's references because the whole passive structure of the component is characterized by a rigorous three-dimensional (3-D) finite-element method. Via this full-wave technique, one could also take into account the indirect interaction between the component and its passive circuit environment, or another component, which is not possible analyzing a complex circuit using a classical segmentation approach.