Analysis of Vivaldi antenna over a heterogeneous ground using a 3-D TLM-CE method

The Vivaldi antenna has been widely studied and applied due to its simple structure, wideband, and high gain. However, calculating the current distribution and the radiation pattern for the Vivaldi antenna over a heterogeneous ground is a challenging problem because of the complex environment. The moment method (MoM) is well suited for solving antenna problems in uniform media, but not suited for modeling the fields in the heterogeneous media. On the other hand, the finite-difference time-domain (FDTD) method and the transmission line matrix (TLM) method are suited for modeling the fields in the heterogeneous media. They are not well suited for solving antenna problems. In order to use TLM method to analyze Vivaldi antenna over a heterogeneous ground, a current equivalency (CE) principle is proposed in this paper. Based on the current-equivalency (CE) technique, a 3D TLM method is able to directly compute the current distribution, input impedance, and the radiation pattern of the antennas. The computed results of the Vivaldi antennas agree very well with experimental results