Employing a Pair of T-Shaped Stepped-Impedance-Stubs Inside the Free Area of Miniaturized Wilkinson Power Dividers With Harmonic Suppression Capable of Operating at Optional Frequencies

Abstract

In this article, a pair of T-shaped stepped-impedance-stubs plays a key role in the structure of a Wilkinson power divider. In the first step, to find a general relation between electrical lengths and characteristic impedances of the mentioned stubs and consequently how the operating frequency can be chosen, an equation based on a mathematical analysis is obtained. Then, by using this equation, several miniaturized Wilkinson power dividers with the same configurations at different operating frequencies and capable of suppressing spurious frequencies are designed. Moreover, in each of these circuits 2nd to 16th unwanted frequencies are suppressed. The simulation results of the designed dividers are in good agreement with the expected responses predicted by the obtained equation. To validate the proposed method, a Wilkinson power divider at 0.85 GHz as a sample is fabricated, and 77.83% size reduction is obtained. Furthermore, the fabricated divider suppresses 3rd to 21st harmonics better than −20 dB.