FastS-parameter extraction method for the analysis of planar structures using the method of moments

Abstract

This article describes a new fast method that yields an S-parameter's description for a structure immediately after solving the method of moments (MoM) matrix. A virtual elongation is added to the line without extra coupling calculations. The line can be excited by imposing traveling waves with the correct propagation constant and current profile on this elongation. The elongation is also used to modify the line's self-coupling matrix (without changing its size) to make it appear as though it is terminated in a matched load at its fed end. The described method allows a close integration between the method of moments and S-parameter circuit solvers.

Fast method for calculation of mutual coupling in planar microwave circuits on general multilayer substrates

“…For circuits, where one is interested in the relations between incoming and outgoing waves on the feeding lines, an additional deembedding step (such as that found in [11]) is therefore required. In [10], the MoM is altered in such a way that incoming and outgoing waves at the structure's ports are just extra unknowns in the coupling matrix, along with the segment couplings. This makes it possible to insert the MoM coupling matrix directly into the circuit simulation (along with lines and discontinuities), thereby providing a close integration between the classical MoM, the new modules, and the S-parameter circuit simulator.…”

“…These modifications make it possible to obtain S-parameters immediately after inverting the structure's Z-matrix, without needing an extra deembedding step. Full details can be found in [10].…”

“…These modules will be discussed very briefly in the next section. More details can be found in [7][8][9][10]. This article will focus mainly on the efforts that are needed to combine these modules and an S-parameter circuit simulation engine.…”

“…In this section we will show how the modules that where described in [7][8][9][10] can be combined with the S-parameter circuit simulator that was discussed in the previous section. Couplings between lines must be filled in at the correct position in the A-submatrix.…”

“…Coupling to meshed surfaces is included by directly inserting the modified (see [10]) MoM coupling matrix, Z, into eq. (1), thus changing to:…”