Applications of pseudo-splines for global surface interpolation in shaped reflector synthesis

Due to problems with series-expansions for interpolations in reflector antenna synthesis alternative interpolating functions providing a unique smooth representation for the entire domain of data points-the quintic pseudo-splines were employed. Two test antennas designed for TELEBRAS (Brazilian Telecommunications Agency) were chosen. The former comprises a shaped reflector synthesized for a cosecant squared beam in the vertical plane with an azimuthally uniform radiation, offset-fed by a standard 90° corrugated horn, for use in a nodal station for point-to-multipoint transmission in metropolitan areas. This design yielded a highly curved surface in both principal planes providing an interesting case study for the present application. The second antenna, comprising an offset-shaped dual reflector system for satellite communications, was chosen due to the requirement of controlling both shapings to meet a prescribed sidelobe envelope, which may be affected by poor surface descriptions