Design of a novel dual-band impedance transformer using coupled lines

This paper presents the design of a novel impedance transformer based on coupled lines. The proposed impedance transformer is capable of simultaneously matching frequency-dependent complex loads to frequency-dependent complex source impedances at two arbitrary frequencies. The closed form design equations are derived analytically. The design is verified by the numerical example. The bandwidth obtained is more than 500 MHz at each operating frequency band, which is feasible for most applications.