Improving Gain of a Broadband Antipodal Vivaldi Array fed by a Tapered Excitation

The application of a tapered excitation to the antenna elements of an array is recommended in order to reduce the height of the sidelobe in the far-field antenna pattern improving the link in the forward direction. To implement a specific excitation function, it is desirable to have a power divider in the frequency range of operation. Here, we present two designs: a) using a broadband equal power divider with a variable attenuator and b) unequal power divider. In both cases, the input excitations are reduced to limit the amplitude of the excitation at a particular port. We have selected three tapered functions: Chebyshev, Kaiser, and the zeroth order Prolate spheroidal wave function. For each tapered excitation, we calculate the spatial power distribution of the far-field H-plane pattern.