A novel design of frequency selective surface with low beam's aberration and insensitive to the beam waist radius of incidence wave in quasi-optical feed system

If the FSS is able to be set in optical path illuminated by the Gaussian beam with arbitrary beam waist radius, low beam's aberration is inspired. The length of the optical path and the size of the ellipsoidal reflectors are compressed to meet the strict limitations of size and weight in spaceborne quasi-optical system. In this paper, the FSS whose unit cell is a circular waveguide with three pairs of ridges is proposed. When the beam waist radius is twice of the wavelength, the high order Gaussian mode is excited by the FSS is less than 5%, so that this structure is suitable to be introduce to the compact quasi-optical system.