The monograph deals with topical issues of analysis and synthesis (according to the specified frequency characteristics) of various nodes of the excited path - filters, directional branches, step and smooth transitions. Four directions are being developed: the theory of quadripoles and eight-poles using wave matrices, the synthesis of step and smooth transitions, the synthesis of directed responders (including the synthesis of multi-step responders), the synthesis of microwave filters . The material presented in the book is designed for engineering and technical workers dealing with the problems of microwave tracts . The book is also of interest to students of radio engineering faculties and graduate students.