A new design procedure for single-layer and two-layer three-line baluns

This paper describes a design procedure for a class of three-line baluns, I t is shown that the three-line balun can be considered as a combination of two identical couplers, Thus, the method developed here uses the design of couplers with an appropriate coupling factor for designing this class of ba luns, The derivation leads to the normal mode parameters for the three coup led lines. Physical dimensions are obtained from these parameters. This pro cedure has been implemented for two-layer configurations and verified by co mparison with results from a full-wave electromagnetic simulation and exper imental measurement.