Design of a miniaturized planar microstrip Wilkinson power divider with harmonic cancellation

In this paper, a compact microstrip Wilkinson power divider is designed and proposed using rectangular shaped resonator cells. The presented resonator cells are used instead of quarter-wave length branches in the traditional structure to reduce the circuit size, increase the bandwidth, and eliminate the unwanted harmonics. The designed resonator behavior is studied analytically and the locations of transmission zeros are investigated using transfer function and LC equivalent circuit methods. The proposed power divider (PD) operates at 2 GHz frequency and suppresses the 2nd to 14th unwanted harmonics. The proposed PD achieves approximately 50% size reduction and 40% fractional bandwidth (FBW). The abilities of desirable size reduction and harmonic suppression along with simple structure and wide FBW make the proposed divider a good choice for the modern communication systems, such as multistage power amplifier applications. The proposed divider is implemented and measured. The measurement results verify the simulation responses.