Double $phi$-Step $theta$-Scanning Technique for Spherical Near-Field Antenna Measurements

Probe-corrected spherical near-field antenna measurements with an arbitrary probe set certain requirements on an applicable scanning technique. The computational complexity of the general high-order probe correction technique for an arbitrary probe, that is based on the Phi scanning, is O(N⁴), where N is proportional to the radius of the antenna under test (AUT) minimum sphere in wavelengths. With the present knowledge, the computational complexity of the probe correction for arbitrary probes in the case of the thetas scanning is O(N^-6), which is typically not acceptable. This paper documents a specific double Phi-step thetas scanning technique for spherical near-field antenna measurements. This technique not only constitutes an alternative spherical scanning technique, but it also enables formulating an associated probe correction technique for arbitrary probes with the computational complexity of 0(N4) while the possibility for the exploitation of the advantages of the thetas scanning are maintained.