Challenges with highly shaped dual gridded reflector antenna for spaceborne applications

摘要

This paper reports a most complex shaping of a dual gridded reflector (DGR) antenna for a stringent requirement. There is a requirement of a service area (India with islands) and 10 spatial isolation zones. This stringent RF requirements awake severe design complexity and challenges, which is addressed here. A physical optics-based optimi-ser is employed for the surface synthesis. The cross-pol degradation due to nearby spatial isolation requirement is identified and counterbalanced. Scattering RF component between two shells is reduced sufficiently to lessen the impact of inter-coastal structure. Inclusion of inter-coastal structure precisely in the analysis results in measured parameters to agree well with predicted response with small deviations. Minimum radius of curvature and minimum inter-shell gap are controlled during surface shaping to optimise edge of coverage (EoC) gain, cross-polarisation discrimination (XPD) and spatial isolation. The Main requirements for the DGR antenna are:- to handle 43.5% bandwidth having dual-orthogonal, linearly-polarised with EOC gain (>27 dBi) and XPD (>30 dB) over a wide landmass coverage and specified spatial rolloff at 10 isolation zones.