Application of the finite-difference time-domain method to the analysis of mobile antennas

In this paper, a review of the finite-difference time-domain (FDTD) method is presented and then employed to model and predict the radiation patterns of three basic configurations of mobile antennas. The directive gain and the input impedance are also calculated. The antennas' configurations considered are a quarter-wavelength monopole mounted on a conducting box, a bent-slot half-wavelength dipole flush mounted on a conducting box, and a quarter-wavelength monopole mounted on the top of an automobile. Three-feed models are discussed and the contour integral is used to model the wire antenna. Transformation of the near field data, resulting from the FDTD, to obtain the radiation patterns is discussed based on the equivalence principle. Radiation patterns obtained using the FDTD compare well with published results.