Genetic algorithm optimization of radar cross section of cylindrical scatterers

The radar cross section (RCS) is one of the most important characteristics of various objects, which have to be located. Various reflectors have been designed on time basis of the well-known corner reflector and have been applied to increase the RCS. The main problems are concerned with the necessity to have a high RCS value in the case of an arbitrary angle of incidence of the wave and with the dimensions of the reflectors. The later problem becomes important for small objects when the use of large reflectors is very undesirable. We propose a new approach to reflector design. The objective of the approach is to increase the electrical dimensions of the scatterers while keeping their geometrical dimensions within a limit of several wavelengths. The increase of the electrical dimensions is connected with concentration of the electromagnetic field energy in close vicinity of a scatterer. It means that the penalty that we have to pay for increasing the RCS will be the resonance property of the reflector and thus the desirable high level of the RCS can be obtained only in a narrow frequency band. Structures formed by cavity backed apertures (CBAs) have been analyzed and it was shown that such structures exhibit strong resonance properties accompanied by a high concentration of the electromagnetic energy in the space surrounding the structures. Structures which comprised of a large number of CBAs are considered and the consequent RCS optimization problem solution by the genetic algorithm is demonstrated.