A Miniaturized Broadband 4 : 1 Unequal Wilkinson Power Divider

This paper presents the design of a miniaturized unequal 4 : 1 Wilkinson power divider operated across a broadband 1 to 11 GHz, which has a compact size with overall dimensions only of 10 mm × 26 mm. By using a simple defected ground structure (DGS), the microstrip line can be realized with very high impedance of over 150Ω, and consequently a 4 : 1 power dividing ratio can be obtained. Meanwhile, the fabrication problems caused by the very thin conductor microstrip width can be prevented. For verification, the measured results of good dividing ratio, better than 10 dB return loss and better than 15 dB isolation across the whole operating band, are also given.