Feasibility Study of Angular Super-Resolution with the Active Surface of a Radio Telescope

The concept of super-resolution refers to various methods for improving the angular resolution of an optical imaging system beyond the classical diffraction limit. A feasible method to design antennas and telescopes with angular resolution better than the diffraction limit consists of using variable transmittance pupils. The simplest transmittance pupils are binary phase shifts masks, also known as Toraldo Pupils, consisting of finite-width concentric coronae which modify the phase of the incident wavefront. In this work we present a preliminary feasibility study to determine if and how the active surface of the 32m Noto radio telescope can be used to modify the wavefront in the same way a Toraldo Pupil would do. Our preliminary analysis suggests that an ideal reflector with fully independent active panels would be able to achieve the super-resolution effect, but the real Noto active surface, where each actuator is connected to four distinct panels, adversely affects the operation of the simulated Toraldo Pupil. We are planning to apply the same analysis to the shaped active surface of the Sardinia Radio Telescope.