Potentially Fast Spherical Near-Field Measurements for General Antennas based on Signal Derivatives

The theory behind spherical near-field antenna measurements places a certain boundary to the number of samples needed for a complete measurement which, subsequently, sets the minimum measurement time, given a specific mechanical scanner speed. Some papers have appeared in the literature addressing this problem, but most of them assume a priori information about the antenna, in addition to the radius of its minimum sphere. The new and unique method presented in this paper may facilitate an almost 50% reduction of the measurement time in spherical near-field antenna measurements by employing, in addition to the received signal itself, also its derivative with respect to the azimuthal angle. Since this method does not assume a priori information beyond the minimum sphere radius, it can be applied universally.