Pattern shaping with a metal plate lens

The metallic parallel plate lens is a viable alternative to both the shaped reflector and the array antenna for beam shaping. A
C
-band antenna using this lens is designed to provide a
csc^{2} \theta (cos \theta)^{1/2}
power pattern over the angular limits of
60\deg-80\deg
below horizontal. The Woodward-Levison synthesis technique is applied to determine the required amplitude and phase distribution across the aperture. Initial plate positions and lengths of the lens are determined from geometrical optics and infinite waveguide theory. The positions and lengths of the lens plates are adjusted experimentally until a satisfactory pattern is obtained.