Design of the broadband balun with the compensated coupled line at balanced ports

A broadband balun with the compensated coupled line at balanced ports has been proposed. The operating fractional bandwidth of the proposed balun is 10% more than that of the conventional Marchand balun. Moreover, the proposed method can be employed for a long connecting segment between the balanced ports with tight coupling at desired frequencies. In addition, summarized graphs are provided as well. Furthermore, a design example is developed to demonstrate the flexibility of the proposed structure.