S. V. Elizarov, Yu. B. Korchemkin, O. N. Smolnikova, A. K. Tobolev

Absorbing materials are proposed for transformation of beam from a reflector antenna of 1.2 m diameter into a fan radiation pattern with low side lobes. The authors use two identical planar metal shields on the reflector separated by 10 cm gap over the axis of symmetry. The layer of radio absorbing material, based on conducting foam polyurethane, is placed on the surface of the shields. The efficiency of this suggestion is illustrated by the radiation patterns, obtained numerically and compared with experimental results. The analysis of obtained results confirms suitability of using symmetrical metallic shields and absorbing materials for required radiation patterns shaping. This type of solution allowed us to increase the width of the main beam of radiation pattern at the -1 dB level from 1,2° to 11,6° with low (more than -20 dB) side lobes level. Experimental results also confirm that the radiation pattern remains narrow (no more 1°) in orthogonal plane. Such a type of antenna allows us to create a quasi-uniform distribution of field in a sector of arrangement of a large-extent antenna under test with providing minimization of the field beyond the indicated sector. The indicated antenna field distribution allows considerable decreasing undesirable reflections in the measurements not only in anechoic chamber but also in an open range.