An accurate analysis of finite-sized Tapered Slot Antennas

A Method of Moments (MoM) model has been developed for the analysis of the Linearly Tapered Slot Antenna (LTSA) on a finite dielectric substrate. An approximate closed form Green´s function is obtained for the infinite dielectric substrate. Galerkin type Method of Moments with Rao-Wilton-Glisson (RWG) basis functions are used in order to solve Electric Field Integral Equation (EFIE) derived for the LTSA. The feed section of the antenna is modelled with a pulse excitation. Finite dielectric substrate region is modelled by equivalent volume polarization currents existing in this region. Modifying the incident field using the polarization current density, and solving for the antenna currents in air yields accurate results without increasing the number of unknowns as in the full-wave model. Comparisons of small and large LTSA patterns with HFFS results are presented to demonstrate the validity of the model.