Miniaturized Unequal Dual-Frequency Wilkinson Power Divider Using Pi-Structure Impedance Transformers

Abstract

This article reports a miniaturized unequal dual-frequency Wilkinson power divider with high suppression and isolation of the intermediate-band signal. To satisfy the requirement of size reduction, arbitrary dual-frequency applications, and unequal power split simultaneously, four compact Pi-structure impedance transformers with symmetric stubs are proposed to replace four conventional quarter-wavelength transmission line transformers employed in the traditional unequal single-band Wilkinson power divider. In addition, the closed-form design equations of all Pi-structure impedance transformers are obtained based on the corresponding analytical solutions, and a single isolation resistor R is used to obtain ideal isolation between two output ports in this proposed miniaturized unequal dual-frequency Wilkinson power divider after rigorous mathematical proof. For verification, simulated and measured results of an unequal (the power-dividing ratio is 3 dB) miniaturized microstrip power divider operating at both 1 GHz and 2.4 GHz are shown, and good agreement between the simulated and measured results can be observed.