Novel Sub-Miniaturized Wilkinson Power Divider Based on Small Phase Delay

In this letter, admittance matrix and arbitrary phase delay is investigated for the design of sub-miniaturized Wilkinson power divider (WPD). A theoretical model based on admittance matrix is derived and discussed to find the relationship among arbitrary phase delay, characteristic impedance and electrical length of WPD. The presented method is validated by building a modified configuration which is centered at 500 MHz with 14.18% fractional bandwidth (FBW) using both microstrip lines and lumped elements. The measured results show that the proposed WPD exhibits excellent performances, including less than 0.27 dB insertion loss, better than 26.1 return loss and greater than 39.2 dB isolation. Moreover, more than 85% size reduction is achieved, compared with conventional WPD.