Analysis of reflector pattern in different frequency ranges in the backward hemisphere

The reflector directional characteristics determination method grounded on the usage of the second kind Fredholm integral equations for "jumping" of the current surface density is offered. When using the thin absolutely conductive unenclosed shield as an antenna, the exact calculation of the distant side and backward radiation is possible if we use the Fredholm first kind integral equations. The solution of the second kind integral equations for the diffraction problems on unenclosed shields with boundary conditions of the Dirichlet and Neumann types are considered. However it is difficult to algorithm the obtained three-dimensional problems solutions in the special functions class. This limits the feasibilities of the numerical method usage when calculating real unenclosed constructions. The purpose of this article is the development of the Fredholm second kind integral representations operation theory for calculation of reflector spatial characteristics as a paraboloid of rotation in quasi-optical range (D//spl lambda/=10). When calculating exactly it is necessary to bear in mind that the behavior character of surface currents in the central part of a reflector and in the boundary zone can considerably differ from each other.