taper length and antenna aperture length for 3GHz vivaldi

can any one tell me how to calculate taper length and antenna aperture length for 3GHz exponential taper vivaldi antenna ?

The slot with at the beginning of the taper determines the maximum radiating frequency; Wb=lambda/2 at fmax
The slot with at the end of the taper determines the minimum radiating frequency; We=lambda/2 at fmin