Stepped transmission-line microwave filters and transformers with improved parameters

The article presents design method of stepped transmission-line microwave filters and transformers with improved parameters. In many situations microwave filters and transformers designed by conventional methods (without discontinuity influence on frequency characteristics taken into account) have not acceptable characteristics. Discrepancy between ideal and measured characteristics increases with frequency because of to large Z_max/Z_min ratio (e.g. d_max/d_min for coaxial line) and large dimensions in comparison to λ. Significant improvement of discussed networks parameters can be accomplished by using optimisation procedures and taking adequate discontinuity model into account. As a result we obtain filters and transformers with very well convergent theoretical and measured characteristics.