A Modified Wilkinson Power Divider With Isolation Bandwidth Improvement

This paper proposes a novel modified Wilkinson power divider with wide isolation bandwidth. The isolation bandwidth can be extended by an additional isolation network (INW) in the circuits. An equal and an unequal 4-GHz modified Wilkinson power divider on FR4 with compact circuit sizes are designed and measured to verify the new design concept. The measurement results show the operation bandwidth from 1.8 to 6.4 GHz with 20-dB isolation in the equal case. In the unequal case, the operation frequency starts from 2.4 to 5.3 GHz with 20-dB isolation. Moreover, a 3-GHz 1-to-3 modified Wilkinson power divider is realized with the operation frequency from 2.05 to 3.83 GHz with 20-dB isolation. These circuits demonstrate that the isolation bandwidth can be extended by an INW, and this INW can be used in many power dividers with different applications. To the authors' knowledge, these circuits provide the widest fractional bandwidth of isolation in a Wilkinson power divider ever reported, except those using multisection structures.