Copolar and cross-polar radiation of Vivaldi antenna on dielectric substrate

The copolar and cross-polar radiation patterns of the Vivaldi antenna on a dielectric substrate are calculated anal validated by measurements. The met hod involves a two-step procedure, The electric field distribution across t he antenna slot aperture is calculated first. The radiated fields are then calculated, using Green's functions. The continuous exponential tapered sha pe is approximated by annular linearly tapered sections, The conical transm ission-line theory and a variational method yield the electric field in eac h section. The radiation calculation is based on closed-form expressions fo r the dyadic Green's function of an elementary electric field source in a c onducting half sheet. Both copolar and cross-polar radiation patterns of th e Vivaldi antenna are calculated by integrating the Green's functions weigh ted by the electric field distribution over the antenna aperture. The effec t of lateral truncation is taken into account by defining weighting pattern s. The method is validated by original measurements and limitations of the model are discussed, Antenna directivity and sensitivity are calculated.