Two-way modified wilkinson power divider for UWB applications using two sections of unequal electrical lengths

Abstract

This paper presents 2-way Power Divider (PD) for Ultra-Wideband (UWB) applications. The proposed power divider is realized using two cascaded sections of Wilkinson Power Divider (WPD) of equal characteristic impedances and unequal electrical lengths with inserted open stub to improve matching, isolation and to broaden the bandwidth. It is proved analytically using the “Even Odd Mode” analysis method and the ABCD matrix to obtain exact closed-form design equations. A detailed design methodology is introduced to facilitate the implementation without needing CAD optimization. To verify the proposed design methodology, a 2-way power divider is designed, fabricated on a Rogers RT/Duroid 5880 substrate and compared to other published 2-way microstrip power dividers. Measured data show good agreement with Electromagnetic (EM)-Circuit Co-Simulation, which proves the design equations and methodology. The proposed planar 2-way PD achieves an isolation = 13.5 dB, input return loss = 10 dB, output return loss = 14.5 dB and exceeded insertion loss = 0.9 dB (over the -3 dB splitting ratio) through the whole UWB range from 3.1 GHz to 10.6GHz. Furthermore, it has a compact area of 22mm × 15mm, which provides 50% enhancement over similar microstrip PD circuits while achieving better isolation and matching.