Design of Low Scattering Strut for Ground Station Antennas to meet ITU Recommendation

This paper investigates the strut designs for ground station antenna, to comply the ITU recommendation for off axis radiation pattern. The conventional rectangular and circular cross-sectional struts have been analyzed in 9.2m Cassegrain optics based shaped dual reflector antenna system. The analysis has also been extended for the rectangular strut with reflecting wedge, the most economical alternative for low-scattering struts. The analyzed secondary performances are evaluated and post-processed to compute the percentage violation of recommendation ITU-R S.580-6 over the angular range for each strut type. The optimization of the wedge angle of the reflecting wedge is carried out to minimize the percentage violation. The presented results reveal that strut incorporating a 45-degree reflecting wedge not only meets the ITU-R Recommendation but also significantly reduces the violation from 32% to as low as 3% as compared to conventional rectangular struts