Design of broadside arrays using iterative interpolation techniques

Arrays having specified beamwidths and sidelobe levels may be synthesized from a simple "seed" array having the required sidelobe level, but a much broader beamwidth than the specification value. An iterative process doubles array spacing at each step. This narrows the main beam by a direct scaling factor of two in sin theta space. The echelon lobes introduced by this action are reduced to the specification sidelobe level values by an interpolation procedure which introduces appropriate element weights at the vacated positions. This 'stretch and fill' tactic may be used repeatedly to obtain any beamwidth desired. The computations of weights for these arrays of any size are trivial and the resulting current distributions have a well-behaved taper. Aperture size requirements and efficiencies are consistent with those of conventional designs for a given beamwidth and sidelobe combination. Supergaining problems are not encountered with this procedure. Interpolation techniques are also used to develop a unique aperture format and excitation matrix combination. This approach to beam steering provides for control of pointing angle through signal level control as opposed to the conventional use of phase shifters for steering.