Modelling and design of a wideband Marchand balun

This paper presents a new lumped element model for conventional Marchand baluns. Analyzed by even- and odd-mode method, the equivalent equations are derived for λ/4 coupled lines. Based on the proposed 5^th-order equivalent circuit for λ/4 coupled lines, the model parameters can be easily calculated by the derived equations. A GaAs monolithic wideband Marchand balun was implemented to verify the model. The EM simulation and experimental results show a good agreement with the model simulation. This model is available in a wide frequency range and makes the design procedure of the Marchand balun faster and more easily.