Andrew G. Repjar

Accurate determination of planar near-field correction parameters for linearly polarized probes

A procedure used by the US National Bureau of Standards (NBS) for accurately determining the plane-wave receiving parameters of both single- and dual-port linearly polarized probes is described. Examples are presented, and the effect of these probe receiving characteristics in the calculation of the parameters for the antenna under test is demonstrated using the required planar near-field theory. The planar near-field theory necessary to accomplish probe correction and to formulate probe parameter errors is presented in a concise and meaningful way to help understand when probe correction is or is not needed. >

Antenna Gain Measurements by an Extended Version of the NBS Extrapolation Method

A General Extrapolation Technique which corrects for the effects of ground reflections in absolute gain measurements is described. It utilizes the Extrapolation Method developed at NBS which, in its present form, utilizes only amplitude versus distance data. However, for broadbeam antennas such as those encountered below 1 GHz, ground reflections may produce unwanted oscillations in the amplitude versus distance data. Hence the data are not amenable to the curve-fitting procedure of the Extrapolation Method. This problem can be overcome by including phase versus distance information to reduce the effects of ground reflections.

Optimized wavelength-sized scalar horns as antenna radiation standards

The properties of beamwidth, directivity, and polarization of wavelength-size scalar horns are analyzed and optimized theoretically and confirmed experimentally to determine the usefulness of such horns as standards. Agreement between theoretical predictions and measurements was good.