Dual-Band Gysel Power Divider with Wide Frequency Ratios and Flexible Impedance Transformation

A compact coupled-line circuit is proposed in this article to design a kind of dual-band Gysel power divider (Gysel, 1975). This circuit inherently consists of three pairs of coupled lines, an open stub, two output extension lines, and two grounded isolation resistors. Besides the high power-handling capability, this Gysel power divider features dual-band operating performance, wide frequency ratios, flexible impedance transformation, etc. Using the transmission-line theory and rigorous even- and odd-mode analysis, closed-form solutions for the electrical parameters are obtained. A practical Gysel power divider, which works at 0.92 and 2.45 GHz, simultaneously, is designed and fabricated for radio frequency identification application. Good agreement between the simulated and measured results verify the correctness of the design theory.