ИСТИНА

Compact range is a special scientific facility designed to perform experiments connected with plane waves, for example radar cross section measurements. To obtain plain wave in indoor experiment, one should use collimator, special device designed to transform spherical wave into a plane one. Several types of collimators are used nowadays, the most common are lens based and mirror based collimators. However collimator itself can act as a new source of errors in measurements. The main source of errors is an unavoidable edge diffraction that ruins the field in target zone. To reduce this effect, several technical solutions are used. Common serrated edge collimators are relatively easy to design and construct. However according to numerous mathematical simulations it’s much more effective to use rolled edge collimators. In this scheme edge rays are reflected to the walls of anechoic chamber. Nonetheless, part of these rays can be re-reflected to a target zone, therefore it is necessary to minimize the effect of edge reflection. Mathematical model of collimator edges, covered with special absorbing material is presented. Boundary evaluation problem is reduced to integral equation, which is solved numerically. Results of simulation are presented.