CASSEGRAIN ANTENNA WITH DECREASED EFFECTIVE SCATTERING SURFACE Russian patent published in 1997 - IPC

FIELD: radio engineering. SUBSTANCE: electromagnetic waves of vertical polarization being incident on the surface of paraboloid mirror 1 get reflected from it, since vector E is parallel with its conductors. The effective scattering cross-section for waves of this polarization is determined by the radius of paraboloid mirror 1. Electromagnetic waves of horizontal polarization freely pass through paraboloid mirror 1, since the vector is perpendicular to its conductors, are incident on the surface of plane ribber mirror 2 and on the surface of hemispherical mirror 8. Since the plane ribbed mirror turns the plane of polarization of the electromagnetic wave that is incident on it, the vertically polarized electromagnetic wave is incident on the internal surface of paraboloid mirror 1, gets reflected from it and, freely passing through hemispherical mirror 8, gets focused on the aperture of feed 3. That part of electromagnetic wave that has got on hemispherical mirror 8 is reflected from it, since vector E is parallel with its conductors, freely passes through paraboloid mirror 1 and gets scattered in space. Since the effective scattering cross-section of hemisphere is always less than that of the feed with equal dimensions non-matched in polarization, employment of such a hemispherical polarized mirror in the Cassegrain antenna sheltering the feed decreases the effective scattering cross-section of the antenna on the whole and, consequently, enhances radar deception of the antenna. EFFECT: enhanced radar deception of airborne antenna. 2 dwg