Experimental Measurement of the Near-Fields of a UHF Horn Antenna.

摘要

The purpose of this report is to determine quantitatively some of the practical limitations of testing in the neat field of UHF horns; in particular, how near to the horn aperature is the field is reasonably uniform in amplitude and phase for a given size test object. This report describes in detail near feild measurements of both the electric (E) and magnetic (H) vectors from the aperture of a UHF horn out to a distance of 4.8 meters. These measurements encompass a rectangular volume of dimensions 2.4m x 3m x 4.8m. The data spatial seperation (i.e., spatial resolution) is0.1m in each orthogonal direction. The E and H field data is analyzed and displayed graphically. Itis analyzed independently and combined to show the wave impedance behavior in the near zone. By observation of the data presented, one can immediately develop engineering guidelines for defining the useful test volume in the near zone of a UHF horn. (Author).