Characteristic modal analysis using a Galerkin shell

The method of characteristic modes is a relatively little used alternative formulation of the method of moments. The paper describes the implementation of a suite of general purpose computer programs for the determination and optimization of characteristics modes for arbitrary structures. The characteristic modes of a number of antenna configurations are then examined. The technique has been found most useful for the design of antenna systems for complex structures, particularly those of vehicles. It is well-known that the characteristics of a particular antenna may be dramatically altered by spurious current flow on the structure on which it is mounted. With characteristic modes however, the antenna and its mounting structure may be considered as one. The determination of its modal set allows the current flow on the complete composite structure to be optimized and hence exploited to beneficial effect