Reflections off aircraft and the shape optimization of a ridged waveguide

The analysis of TE and TM waves traveling down a guide is a well-known art. However, it is the inverse problem that is more relevant in industrial design. That is, for a given cut-off frequency or attenuation limit, to synthesize the guide. The methodology for solving this inverse problem is laid down and demonstrated using a ridged guide as example. The procedure relies on defining an object function and minimizing it using its gradients with respect to the parameters of design interest.