A design approach for small arrays of dielectric-free Vivaldi antennas to minimize truncation effects

Numerical simulations of small, wide bandwidth Vivaldi tapered slot antenna arrays have revealed that certain characteristics of the isolated Vivaldi element are indicators of the antenna´s performance in small phased arrays. This result is somewhat surprising, since multioctave bandwidth scanning arrays are strongly influenced by mutual coupling. In small arrays, the resistance maxima associated with (typically weak) resonances of the isolated element seem to be accented. Weakening the lowest resonance and equalizing other resonances of the isolated element leads to antenna designs that perform better in small arrays.