Finite-width gap excitation and impedance models

In this paper, we present a new method for the feed model for the method of moments (MoM). It is derived from a more accurate model with the realistic size of the excitation, in order to replace the commonly-used delta-gap excitation model. This new model is formulated around the electric field integration equations (EFIE) where the terms for magnetic current and magnetic field can be removed. Hence it is much simpler to implement and reduces the numerical complexity. In addition, a variational formulation is derived to provide second order accuracy of the input admittance calculation. Moreover, this new formulation can be easily extended such that one can insert passive load elements of finite size onto the distributive network, without complicated modification of the MoM analysis. This allows simulation of many realistic networks which include load elements such as resistors, capacitors and inductors.