A Novel Structure for Ultra Broadband Broadside- Coupled Impedance Transformer
In this paper, the authors present a novel structure for ultra-broadband 4:1 broadside-coupled PCB impedance transformer. Analysis, simulations and measurements of the developed transformer are given and discussed. Three prototypes of the proposed structure are implemented (Trafo I, Trafo II and Trafo III) at resonant frequencies 2.3, 1.3 and 0.85GHz, respectively with Fractional BandWidth (FBW) of greater than 400%. The implemented transformers show an ultra-broadband performance with a transmission loss of less than - 1 dB and return loss of at least - 10 dB in the desired bandwidth.