Synthesis of power radiation patterns for linear array antennas

A novel method of designing the aperture illumination of an N-element linear array of equispaced radiators to produce an approximation to a specified beam shape is described. The method essentially consists of selecting a `scanning function¿¿, which itself is a physically realisable power pattern for the array. Convolution of the scanning function with the desired power pattern gives the physically realisable approximation to the desired pattern, here termed the `realised power pattern¿¿. A suitable choice of scanning function can provide desirable properties such as freedom from ripple in the angular passband and extremely low sidelobes. In theory, there are 2(N¿¿1) different illuminations which can produce the same power pattern, but in practice only a fraction of these correspond to illumination functions having significantly different shapes. The different illuminations produce different far-field phase patterns and guidance is given on how to select this phase pattern so as to exercise some control over the general shape of the aperture illumination.