Phaseless Spherical Near-Field Antenna Measurements With Reduced Samplings

The ever-growing complexity of radiating systems asks for always more challenging radiation pattern characterizations requiring time consuming field acquisitions and high-cost facilities. Consequently phaseless, or magnitude-only, measurements have recently regained of interest as they prevent the tedious and difficult task of phase acquisition. Consequently, it allows the use of cheaper or more versatile measurement setups like drone measurements or easier high-frequency measurements. However, the difficulty is shifted to the notoriously difficult resolution of the phase retrieval (PR) problem, the instability of which is commonly mitigated by the acquisition of a large number of phaseless field samples. A procedure enabling a reliable and accurate phaseless antenna measurement from a reduced number of spherical near-field (NF) samples based on the two scan technique is proposed. Its efficiency and stability, that relies on the systematic determination of a good starting point, is validated by representative simulations and experimental cases performed on various antenna structures.