Determining the First-Null Mainlobe Region of an Arbitrary Pattern for 2-D Numerical Pattern Synthesis Algorithm

Determining the mainlobe region of an arbitrary pattern is a critical problem in the two-dimensional numerical pattern synthesis (2-D-NPS) method in which a number of artificial interferences with appropriate powers are distributed outside of the mainlobe region. In this communication, a novel mainlobe region determination procedure based on the seeded region growing (SRG) method is proposed. Two different stopping criterions are introduced. Several numerical synthesis examples for uniformly and nonuniformly spaced planar arrays as well as a cylindrical array with directive elements, are presented to validate the effectiveness of the 2-D-NPS with the proposed mainlobe determination procedure. The two stopping criterions are also compared with these examples.