Design of high precision lens or reflector antenna systems for CubeSat MMW/ SMMW radiometers

Summary form only given. The fidelity of brightness temperature data obtained from radiometers is largely dependent on the accurate prediction of its lens/ reflector antenna system pattern. It is hence crucial to know, with high precision the antenna system´s spillover, main beam and ohmic efficiencies as well as the feed´s phase center. Although the Gaussian (paraxial) beam mode analysis is a reasonable first order approximation for such an analysis, its accuracy is limited off-axis for millimeter and sub-millimeter wavelength diffraction fields. The purpose of this study is the rigorous analysis of the complex diffraction field due to a feed at the lens aperture, within the dielectric lens and at the far field. This analysis leads to the determination of an optimal lens profile such that the main beam efficiency of the system is maximized. An optimized matching function at the planar surface of the lens is also obtained that minimizes reflection losses. These techniques can also be applied to reflector antenna systems.