Analysis of Performance Degradation due to Mechanical Errors during the Deployment of Rib-Type Mesh Reflector Antennas

This paper analyzes performance degradation caused by mechanical errors in rib-type deployable mesh reflectors to propose error tolerance levels that can be used as a reference when designing antennas composed of these reflectors. In rib-type deployable mesh reflectors, five types of errors may occur: joint stop angle error, feeder alignment error, feeder pointing error, defective surface error, and wrinkled surface error. In this study, antenna performance degradation stemming from these mechanical errors are analyzed, and error tolerances corresponding to a reduction in the boresight gain by 1 dB (20.6%), 2 dB (36.9%), and 3 dB (50%) are suggested. These boresight gain reduction levels are widely adopted as intuitive indicators of antenna performance degradation. In addition, the corresponding variations in half-power beamwidth, sidelobe level, and main lobe direction are calculated for each error case. The error tolerances at which a performance degradation of 1 dB occurs for each error type are as follows: 0.32° at 10 GHz for joint stop angle error, 9.5% at 3 GHz for defective surface error, 0.0071 m at 10 GHz for wrinkled surface error, 0.016 m at 10 GHz for feeder alignment error, and 23.6° at 3 GHz for feeder pointing error. These results reveal that the most sensitive and critical error is the joint stop angle error, which must be significantly minimized when designing and fabricating rib-type deployable mesh reflector antennas.