Circular-aperture pattern with ultralow sidelobes

The radiation pattern from a circular aperture with symmetrical inphase illumination can be described by a Neumann series of the form ¿{anJn(u)/u}. A trial series of patterns with variable an has given one pattern in which the sidelobe level is nowhere greater than ¿47 dB in the computed range u ¿ 15. The aperture distribution required to obtain this pattern is derived by a simple synthesis technique applicable to this form of series description of the radiation pattern.