3-D absolute gain pattern measured by 1-D circular near-field to far-field transformation applied to elongated antennas as base-station antennas

We propose a novel 3-D absolute gain pattern measurement method using 1-D circular near-field to far-field transformation (1-D CNFFFT) for elongated antennas such as base-station antennas. By combining a few 1-D cut plane patterns and the far-field optimal sampling interpolation (OSI) expansion, we can obtain the 3-D absolute gain pattern. In experiment for a base station antenna at 2 GHz band, we demonstrate that the 3-D absolute gain pattern measured by the propose method agrees well with the 3-D pattern measured by the conventional cylindrical near-field scanning.