On the influence of the field acquisition domain regarding Near-Field to Far Field-transformation

A study of the influence of the NF acquisition domain on the transformed FF has been presented. The presented results show the relationship between the truncated spherical NF acquisition domain, the equivalent sources domain size and the FF angular region of validity. The interest of working with truncated NF spherical acquisition domains is related to the high-directive antennas with low secondary lobes, where almost all the power is concentrated in a narrow main beam, also in the NF region. For these antennas, a spherical NF measurement using scanning in phi and step in theta, joint to the presented properties of the NF truncation domain to the main beam region supposes an interesting time-saving method for NF-FF transformations.