Design and analysis of a four-wire antenna for anechoic chamber illumination.

摘要

In this dissertation a four-wire antenna is introduced for use in electromagnetic compatibility and other electromagnetic measurements. The four-wire antenna consists of two V-antennas that also form V geometry with each other. The antenna is designed for use in a tapered anechoic chamber and to provide a uniform field in a given test region over a wide frequency range.;The antenna was first analyzed in free space. In order to remove reflections at the ends of the wires, an appropriate loading resistance was determined. The free space analyses show that the antenna produces a field uniform within ;Since the antenna was installed in an anechoic chamber, the effects of absorbers were also considered. To study these effects, volume-surface integral equations (VSIEs) were modified to apply to infinite periodic structures. Using these modified VSIEs, the wedge type absorbers were reduced to equivalent lossy layers of similar electrical properties (reflectivity). Then the entire anechoic chamber, including the four-wire antenna, was analyzed using the finite element technique.;The four-wire antenna was constructed and installed in the anechoic chamber at the Radiation Laboratory of the University of Michigan. The field deviations were measured and are within ;To show the potential of the four-wire system for electromagnetic interference and compatibility applications, sample measurements were performed. These include induced surface field measurements on spheres and aircraft models, and backscatter measurements from a cylinder.