Displaced-axis-ellipse reflector antenna for spacecraft communications

This work discusses the electrical characteristics of axially-symmetric dual-reflector antenna systems based on the axially displaced ellipse (ADE) configuration, with emphasis on its application in compact high-gain high-efficiency spacecraft communication antennas. Relevant ADE electrical properties are compared with the corresponding characteristics of the Cassegrain geometry (a configuration commonly used in high-gain spacecraft applications). It is shown that the ADE is capable of operating efficiently with electric apertures considerably smaller than the Cassegrain geometry, an important feature for small spacecraft. To demonstrate the outstanding electric performance that can be expected from the ADE, the predicted and measured results of an X-band 1250 mm aperture diameter prototype are presented.