A Balanced-to-Single-Ended Wilkinson Power Divider

Abstract A balanced-to-single-ended (BTSE) Wilkinson power divider of planar microstrip structure is proposed in this paper. It has a balanced input and two single-ended outputs. Cascade of a balun and a conventional power divider can be replaced by this proposed structure. Based on the theory of mixed-mode S parameters and the admittance matrix method, the critical parameters are determined. The four-port network is analyzed by simplifying it to two-port network with other ports matched at the central frequency. Then the key parameters are derived and the impact of a freely selected variable on the bandwidth is also discussed. An example of 2.4GHz BTSE power divider is designed. The simulated and measured results show the effectiveness of the method: differential-mode transmissions are better than −3.25dB, common-mode transmissions are lower than −28.6dB, common-mode return loss is −0.10dB, differential-mode return loss and isolation is lower than −23.7dB. While the operating bandwidth is 20%.