Optimization of a scattered signature

The optimization of electromagnetic devices governed by the Poisson equation is now well established. This paper extends the methodology to scattering problems. In particular, the permittivity and permeability of the coating on an aircraft fuselage and its thickness are computed so as to minimize the scattered signature. It is shown that the reflection coefficient has multiple minima and maxima as the thickness of the coating is varied, thereby making search techniques superior to the usually efficient gradient methods. On the other hand, as the permeability and permittivity are varied, the reflection coefficient varies gradually to its one minimum, except for a few local minima, thereby making gradient techniques very powerful