A general approach to the design of planar array antennas for forming of multiple orthogonal beams

A general approach to the design of the aperture part of planar array antennas forming an arbitrary cluster of orthogonal beams specified in a periodic lattice of direction cosines in the coordinate system related to the array aperture is proposed. The approach includes determination of the aperture dimensions and shape, as well as the array lattice type and the number of the array elements. The role of the embedded array element pattern for providing beam orthogonality and the relation between a specified number of beams and the necessary minimum number of the array elements are discussed. Some demonstrative examples of the beam clusters and appropriate array configurations are considered.