The demands of sensitive and accurate modelling of a system by electromagnetic field solver is a central problem in design and plays an important role due to the continuing development of the Computational Electromagnetics (CEM) methods. This paper gives an overview of suitable methods and then presents several practical applications. The power and requirements of hybrid methods is shown. These methods are also needed for the design of antennas e.g. for cellular phones and the related Electromagnetic Compatibility (EMC) impacts on human beings.