Design method of new power divider employing zero-degree transmission line with arbitrary power dividing ratio

Abstract

In this paper, a new structure of power divider (PD) employing zero-degree transmission line (TL) with arbitrary power dividing ratio is firstly proposed. Detailed analysis is performed according to the modified even- and odd-mode analytical method. This procedure shows that the resistor between the two output ports corresponds to the wide isolation band, while the other two grounded resistors can not only realize the two output ports matching, but also provide better power handling capability in comparison with the conventional Wilkinson PD. Specifically, a zero-degree composite right- and left-handed (CRLH) transmission line (TL) is used in the PD structure, which results in a smaller size, higher design flexibility, and wider operating band than the conventional Gysel PD with the reference of 10-dB return loss and 1-dB insertion loss. Closed-form design equations are derived, and the proposed design theory is verified by two PDs with the same centre frequency but different power dividing ratio (P2/P1) as 1:1 and 2:1, respectively. According to the experiment results, both PDs have a better out-of-band rejection than the conventional Wilkinson PD, more than 100% fractional operating bandwidth under full port matching, and more than 85% isolation bandwidth with the reference of 15-dB S32.