DETERMINATION OF ANTENNA RADIATION PATTERN FROM NEAR-FIELD MEASUREMENTS

Abstract

This thesis oresents a study of two fundamental problems in antenna theory: determination of antenna far-field radiation orooerties from near-field measurements, and computation of the near-field mutual coupling between two antennas arbitrarily oriented and separated in free space, given the complex electric far-field pattern of each antenna and the geometrical factors that describe the relative orientation of each antenna. Both problems are based on plane-wave scattering-matrix (PWSM) theory of antennas. Plane-wave scatterinq-matrix theory was introduced by D.M Kerns. It is a qood basis for advanced antenna theory. Its formulation is obtained by enclosing the antenna between two planes and considerinq the incident and scattered plane-waves on both planes. It specifies the linear transformation from the incident part of the field to the scattered part of the field. It considers the antenna as a multipart transducer which can be fully described using the s attering parameters.

The far-field radiation properties (such as far-field pattern, power gain, effective receiving area and polarization parameters) can be determined from near-field measurements. Near-field measurements mav be either probe-corrected or non probe-corrected. Near-field measurments may be planar (plane-rectanqular or olane-oolarl or spherical or cylindrical