ABSTRACT
Analysis and design of such networks is made more systematic by the introduction of the concepts of multiport networks as used in lumped-element circuit theory. There are, however, certain aspects of this formalism that are special to the inclusion of transmission lines in the network. The authors show how the reciprocity property follows from the properties of the lumped elements and transmission lines which constitute the network. Finally, occasional use is made of the image parameters of a two-port network. Image parameters are used in the classical design of filters, and in the design of long transmission circuits in which an impedance match must be maintained. A hybrid network is a four-port network in which, when matched loads are placed at each port, an incident wave at one port is split in some ratio and delivered as outgoing waves at two of the remaining ports, while there are no outgoing waves at the incident port or the last remaining port.
