Charakterisierung mehrschichtiger Materialien für Mikrowellenfrequenzen mit Hilfe eines evolutionären Algorithmus

Abstract

One important topic of the Signatures team of the German Aerospace Center in Oberpfaffenhofen near Munich is the determination of the complex permittivity of materials. Beside analytical methods regressive calculation scripts are used. The calculation is based on reflection and transmission measurements for microwaves within 1 and 110 GHz. A material which consists of an arbitrary number of plane layers is still a great challenge. The already available calculation methods are not capable of computing the permittivity of each layer. In this work an evolutionary algorithm which tries to overcome this problem is developed. The algorithm is part of a regressive calculation environment and it is designed to compute the real and imaginary part of each layer’s permittivity. Moreover the thickness of each layer is varied during the calculation process in order to optimize it. In this work the number of layers is limited to three, which does not restrict the usual tasks of the team.