Modeling electrically small structures in layered medium with augmented EFIE method

Electrically small structures embedded in a planarly layered medium are modeled by the augmented electric field integral equation (EFIE) method in this paper. By separating charge as extra unknown list, and enforcing the current continuity equation, an augmented EFIE (A-EFIE) can be setup. The matrix-friendly formulation of layered medium Green´s function is applied and the frequency scaling of the impedance matrix in the moment method is analyzed when the frequency tends to zero. Rank deficiency and the charge neutrality enforcement is also discussed in detail. Numerical results show that the low frequency breakdown of electrically small structures embedded in a layered medium can be effectively remedied by this A-EFIE method.