Efficient Transmission Line Modeling Sensitivity Analysis Exploiting Rubber Cells

The adjoint variable method is applied for the first time to perform sensitivity analysis with transmission line modelingexploiting rubber cells. Rubber cells allow for the conformal modelingof off-grid boundaries in the transmission line modeling computational domain usingmodified tensor properties. The scatteringmatrix of the rubber cell is analytically dependent on the dimensions of the modeled discontinuities. Usingthis property, an exact adjoint system is derived. The original and adjoint systems supply the necessary field information for the rubber cell based sensitivity calculations. Our technique is illustrated through sensitivity analysis of waveguide filters. The estimated sensitivities are used for fast gradient-based optimization and tolerance analysis.