Impact of Main Reflector and Feed Structural Uncertainties on Antenna Performance

Due to the continuous enhancement of pointing accuracy, detection range, and other performance metrics, reflector antennas are evolving toward high-frequency bands, increased gain, and overall improved performance. In this context, the influence of structural uncertainties, such as antenna feed and main reflector accuracy, on performance has become notably prominent. The inherent interdependence between structure and electromagnetic properties accentuates the impact of structural and electromagnetic uncertainties on electrical properties like gain and pointing of reflector antennas. Addressing the challenge of analyzing the impact of uncertainty on antenna performance and ensuring optimal functionality, this paper derives the phase interval resulting from feed position deviations in the aperture plane. Additionally, it investigates the influence of feed direction uncertainty on the amplitude of the aperture plane and provides an expression for the pattern under main reflector shape uncertainty. Building upon these analyses, an electromechanical coupling model for the structural uncertainty of the reflector antenna is established, unveiling the influence mechanism of key structural uncertainty factors on electrical performance. To illustrate these concepts, a calculation example is presented using the 110 m antenna design model from Qitai. The discussion delves into the profound impact mechanisms of feed and main reflector uncertainties on antenna gain, side lobes, pointing, and other performance aspects.