Controlling the far-field resolution in near-field antenna characterization

One of the key points in near-field antenna characterization concerns quickly fulfilling the measurements and rapidly processing the collected data. Recently, we have developed a near-field technique that, by exploiting information on shape and size of the Antenna Under Test (AUT) and adopting a proper representation of the aperture field, is capable to drastically reducing the number of near-field samples as compared to more standard sampling procedures. By doing so, “full resolution” far-fields are obtained. Nevertheless, whenever far-fields with “limited resolution” are of interest providing a rough AUT characterization, then, depending on the degree of satisfactory resolution, the number and locations of samples can be tuned accordingly, and, thus, the measurement duration can be further reduced. We introduce an approach capable to properly controlling the degree of resolution of the reconstructed far-field to control, in turn, the near-field sampling. This is achieved by a proper representation of the aperture field. Numerical results are presented for the proposed technique in a planar geometry.