The analysis of a segmented paraboloidal reflector with hexagonal flat sections

Segmented reflectors are an important sub-category of reflector antennas where the smooth compound curvature of the reflector is approximated by many small flat sections. The general dynamics (GD) paraboloidal truss antenna described by Fager and Garriot (1969) consists of a large number of hexagonal flats. This antenna was initially intended for space deployment, but this antenna appears to be suitable for terrestrial applications as well. Like most terrestrial reflectors, the GD antenna, consists of both a reflector and a backing structure, yet has demonstrated considerably reduced weight and volume (when folded for shipping) over usual fabrication methods currently in use. The GD antenna, is reminiscent of Buckminster Fuller´s Montreal ´67 Expo double layer dome. Both the backing structure of the GD reflector and Fuller´s dome use a octahedron-tetrahedron (OCTET) truss. Thus, some of the techniques used by civil engineers in the design of large clear span structures could be used in the design of large reflectors, as, for example, earth terminal antennas for satellite communications or radio astronomy antennas. The GD reflector is a tensile mesh net consisting of hexagonal flats. A modified version has pentagons, tetragons, and truncated hexagons along the rim to more closely approximate a circular rim reflector. Thus, it would be desirable to compute the radiation patterns due to polygonal segmentation. Heretofore, reflectors with surface errors would be analyzed by statistical means such as those shown in Ruze´s paper (1966). The line integral method, described here, provides an accurate deterministic method of field computation.