Out-of-Phase Power Divider with Complex Impedance Transformation Based on Miniaturized Isolation Network

A compact three-layer circuit structure based on the double-sided parallel-strip lines (DSPSLs) is proposed in this article to design an out-of-phase power divider (PD) with miniaturized isolation network. This PD, of which the source- and load-impedances are both complex, consists of three DSPSLs for the signal transmission, a conduct plane in the middle, and two resistors for high outputs isolation. The traditional even- and odd-mode method is used to obtain the close-form equations of this proposed PD, and its scattering parameters are also derived. Finally, a practical out-of-phase PD, which operates at 1.8 GHz, is designed and fabricated. The simulated and measured results in terms of scattering parameters as well as the phase difference of two output signals show that this PD features equal power division with out-of-phase, good ports matching, and high isolation, which verify the design theory.