A compensation technique for positioning errors in planar near-field measurements

Abstract

Probe positioning errors are among the major sources of inaccuracy in the planar near-field-far-field transformation technique, as their presence destroys the Fourier-transform relationship between the tangential components of the near field and those of the plane-wave spectrum of the test antenna. An optical systematic correction technique is developed which requires only the knowledge of the true probe positions. The 'corrected' values are computed by an iterative procedure which turns out to be rapidly convergent and fairly accurate even in the presence of rather high displacement errors. It is concluded that the developed correction technique either includes or compares favorably with alternative methods. It is an optimal generalization of the Z-correction method, being exact in principle and allowing simple control of the attainable precision. >