Abstract: This paper first describes a necessity of far-field constructed from near-field measurements for the future satellite's antennas. The first part of this paper discusses a plan-polar near-field technique. By means of the Lorentz reciprocity theorem and The Jacobi-Bessel series expansion the transform formulas from near-field to far-field have been developed. Once the phase and amplitude distributions are sampled by a scanning probe in a plane-polar configuration, the measured data may be transformed into the far radiataed field using the above formulas. Finally, an automated planar near-field measurement system program-controlled by a microcomputer is presented.In the second part of this paper we have summarized some recent results in NBS on upper-Bound errors in far-field antenna paramefers determined from planar near field measurements. Some important formulas and relationships are presented. They may be used for evaluating the maximum errors of far-field paramefers produced by planar nearsfield measurements.They also can provide useful guidelines for design of near-field measurement technique.