Flatness Scanning and Superdirectivity in Planar Antenna Arrays: An Analysis and Design Approach Using IDMBSA

This letter focuses on the important challenge of realizing superdirectivity at large scanning angles (achieving flatness scanning) from the perspective of the array factor (AF). Upon analyzing the derivation of the AF theory, this letter determines that the directivity of planar arrays drops as cosine of the angle (the cosine law) is the result of an approximate derivation. This indicates that an aperture field can exhibit superdirectivity at large angles. Subsequently, we employed the inverse design method based on spectral analysis starting from arbitrary phaseless radiation pattern formerly proposed by us to design a series of aperture fields, which realizing superdirectivity, achieving flatness scanning, breaking the cosine law. The numerical simulation results aligned with expectations, verifying the correctness of the analysis. Further, we can use this property to compensate for the element factor, and thus, achieve flatness scanning. This study provides a useful reference for designing antenna arrays with superdirectivity and flatness scanning.