TWO-MIRROR ANTENNA Russian patent published in 1997 - IPC

FIELD: microwave antenna devices for space and relay communication. SUBSTANCE: device has main mirror with parabolic generatrix, emitter 2 and additional mirror 3 with elliptic generatrix, and cone flange 4 which is mounted on edge of additional mirror 3. Cone flange surface which is directed to main mirror 1 has concentric grooves 5 which are coaxial to symmetry axis of main mirror. Depth of walls of grooves is equal to t = 0,02λ_min, where h_i is minimal wavelength of operating range. Height of grooves s_i and width is λ_min are periodically decreased in direction of outer edge of cone flange 4 with constant coefficient K = 1.08-1.1; i = 1, 2, 3, ..., N is groove serial number. Height h₁ and width s₁ of first groove from symmetry axis of main mirror 1 are equal to h₁= 0,2λ_max and s₁= 0,1λ_max, respectively. Distance between symmetry axis of main mirror 1 to first ring groove is equal to R = (D/2+t),; number of ring grooves N is equal to , where D is extern diameter of additional mirror; is overlap coefficient of bandwidth; λ_max is maximal wavelength of bandwidth; f_l,f_u are respectively upper and lower limits of bandwidth. EFFECT: suppression of influence of additional mirror on emitter in wide bandwidth. 2 dwg