S-parameter Sensitivity Analysis of Waveguide Structures with FEMLAB

Li, D., Nikolova, N.K.
Computational Electromagnetics Research Laboratory, Department of Electrical and Computer Engineering, McMaster University, Hamilton, Ontario

For the purpose of accurate and efficient design of a microwave structure, sophisticated optimization techniques are typically used.

The optimization process can greatly benefit from the availability not only of the objective function, but also its gradient. Numerical electromagnetic solvers do not provide the gradient information, thus defaulting to the finite-difference approximation at the response level. This, however, requires n additional perturbed structure analyses where n is the number of design parameters.

Here, we propose a self –adjoint variable method, which does not require any additional simulations.

We investigate self-adjoint problems in the framework of the finite-element method (FEM). Two 2-D examples, an H-plane waveguide bend and a dielectric waveguide filter are simulated in FEMLAB® 3.1 to test the theory. Numerical results are presented.