Ultra-wide frequency band multichannel quasi-optical feed network design method and system

The invention discloses an ultra-wide frequency band multichannel quasi-optical feed network design method and system, and the method comprises the steps: converting an antenna feed beam width parameter into a Gaussian beam waist radius of a corresponding frequency band according to a stationary orbit microwave radiometer, and enabling the Gaussian beam waist radius to serve as an input parameter of a quasi-optical feed network; according to the insertion loss index of the quasi-optical feed network, carrying out different polarization channel separation by adopting a polarization grid; a shared ellipsoidal reflector is adopted to converge beams, and the size of a quasi-optical feed network device is reduced; a folding layer ellipsoid reflector or a plane reflector is added to carry out folding layer layout on partial channels to form a double-layer compact quasi-optical feed network; parameters of the multi-channel shared ellipsoidal reflector are optimized to reduce channel beam distortion; and completing j