Full-wave design of corrugated conical feeds by the adjoint network method

Full-wave design of corrugated feeds is generally accomplished by repeated numerical analysis of different feed geometries as obtained by slightly varying the geometrical dimensions of the corrugations. Since each corrugated feed may contain hundreds of discontinuities, the above procedure is very time-consuming. In order to reduce the numerical effort, the adjoins network method (ANM) has been applied to design and sensitivity analysis of radiating structures, i.e. to conical corrugated feeds. By using the ANM all the sensitivities of the scattering parameters with respect to the variation of geometrical dimensions are obtained with just one analysis of entire network. When a particular geometrical parameter is varied, only the discontinuity containing that parameter need to be analysed; the overall sensitivities are calculated by means of a simple formula. Corrugated feeds have been designed by using the ANM, they have also been built and measured so as to demonstrate the accuracy and efficiency of the proposed approach.