CAD procedures for planar re-entrant type couplers and three-line baluns

A generalized network model for coupled multiconductor transmission lines is derived based on normal mode parameters. The model is used in the design of planar re-entrant type couplers. By using this network model, the design of a planar re-entrant coupler can be derived from the design of a traditional two-line coupler. The design procedure for single-layer planar baluns using three-conductor transmission lines has also been developed based on this network model. Design procedures and examples are presented.<<ETX>>