Topics in the Design of Insertion Loss Filters

This paper combines the theory of scattering matrices and the design of filters on an insertion loss basis. It is not intended to add substantially new results. Its purposes are to simplify the presentation of the insertion-loss theory, with the help of the scattering parameters, and to study a number of particular cases serving as a guide in practical design and as a starting point of approximate formulas for numerical work. The particular cases and approximate formulas give the designer an appreciation of the influence of various parameters, before the design is crystallized and the accurate computations are begun. The first part of the paper develops properties of general reactance networks, terminated in resistances, and of the special class of such networks which are either "symmetric" or "antimetric." Then the general theory is applied to the design of filters with Tchebycheff behavior in the pass band.