Shaped Prime-Focus Reflector Antenna for Satellite Communication

This letter is concerned with the design and analysis of a dual-polarized center-fed-shaped reflector antenna presently implemented for satellite communication. Design challenges for such an antenna have been outlined herein. A novel hybrid surface shaping technique is devised that employs both global and local surface profile variables using a blend of Zernike polynomials (for globalized shaping) and spline functions (for localized shaping). TICRA POS software, a physical optics (PO)-based optimizer, is employed for the surface synthesis. This hybrid approach for shaping provides additional degree of freedom for surface optimization. Subsequently, scatterers, such as spars, feed system, feed-struts interface, etc., are modeled for the first time by importing respective quadrilinear (quad) meshes and analyzed using a combination of PO/physical theory of diffraction and method-of-moments methods in TICRA GRASP software. Inclusion of scatterers in the analysis results in measured parameters agreeing well with predicted response with little deviations. Minimum radius of curvature is controlled during surface shaping to optimize cross-polarization discrimination (XPD) as well as to meet fabrication constraints. The key requirement for the antenna to handle 17% bandwidth having dual-orthogonal linearly polarized function with edge of coverage gain (>26 dBi) and XPD (>27 dB) over a wide landmass coverage coupled with low volumetric space is adequately met.