H.F. transmission line networks

The paper is concerned primarily with the properties of "re-entrant" networks. These consist of two sections of transmission line joined at their ends, thus forming closed loops. The electrical properties depend primarily on the electrical lengths of the two limbs of the network, the secondary parameters being the attenuation coefficients of the waves travelling along the limbs, the angles at which the branch line joins the main line, the relative geometrical dimensions of the network, and the spacing between the conductors of the transmission line. It is shown that, for practical purposes, the important parameters are the electrical lengths of the two limbs and the attenuation coefficient, and suitable formulaelig involving these quantities are derived. The features and properties of typical networks are fully explained, some being designed for frequency matching at two frequencies and others for use as filters.