In this paper a procedure is presented, allowing the

automatic design of circular polarized radial line slot antennas,

with either pencil or shaped beam patterns. The antenna slot layout

is refined by an optimization scheme based on the physical picture

behind the working mechanism of the array. The validity of the

approach has been proved by designing very efficient pencil beam

antennas, either with maximum directivity or with controlled side

lobe levels, and a shaped isoflux beam antenna