On the modeling of radiation from cables attached to multi-layered printed circuit boards

A simple model for the full wave electromagnetic simulation of common mode radiation from a configuration of a printed circuit board with an attached wire is presented. The cable is treated as an extension of the ground plane and the complete current distribution is evaluated. The solution technique consists of exploiting the convolutional form of the electric field integral equation and fast iterative methods. By a judicious choice of basis functions to represent the magnetic vector potential and by a using a weak representation, the discretized set of linear equations can be written in a simple algebraic form. All operations are kept at a vector level and the need to evaluate and store the electromagnetic interaction matrix is avoided. Consequently, the method presented is capable of handling a very large number of unknowns. Numerical results are presented to show the effect of attached cables on the radiated emission levels. The effect of using ferrite sleeves and segmented ground planes for the reduction of common mode current has been illustrated numerically.