Analytical Expressions for Field-based Response Sensitivity Analysis and Their Application in Microwave Design and Imaging

Almost twenty years ago, field-based adjoint response-sensitivity analysis emerged as a critical aid in accelerating gradient-based optimization as well as tolerance and yield analyses with full-wave electromagnetic simulations. This research effort delivered. Some commercial software packages now offer fast sensitivity analysis, which does not require parameter perturbation thus producing the response derivatives with modest computational overhead. Analytical response-sensitivity expressions have also been derived and they led to breakthrough developments in microwave imaging. Here, the main formulas for analytical response sensitivity analysis are summarized and generalized. Their importance is highlighted through examples in design optimization and in imaging along with an outlook to future developments.