Design of a novel dual-band impedance transformer

This paper presents the design of a novel coupled line based dual-band frequency dependent complex load impedance transformer. The proposed impedance transformer is capable of simultaneously matching the frequency-dependent complex loads having different values at two arbitrary frequencies (closely spaced/widely spaced) to real source impedance, ZS. The design equations are derived analytically to achieve the exact closed-form solutions. The design is verified by numerical simulations in circuit simulator. The bandwidth obtained is more than 320 MHz and fractional bandwidth is more than 11.85% at each operating frequency band, which is feasible for most applications.