Symbolic analysis of linear microwave circuits by extension of the polynomial interpolation method

This paper describes a new approach for the symbolic analysis of microwave circuits, based on the Polynomial Interpolation (PI) method. The latter has been widely presented in the literature as one of the most suitable symbolic analysis techniques for the computation of network functions when the only circuit variable is the complex frequency p(p=jω). An extension of the polynomial interpolation method that allows us to determine, for arbitrary linear circuits, the transfer functions in a fully symbolic form is presented. Then, a description of how the new method can be used to compute microwave performances, such as scattering parameters and reflection coefficients, is detailed. The proposed method was implemented in a computer program called SYSMIC (symbolic simulator of microwave circuits), for both DOS and IBM Unix environments