Analysis and design of out-of-phase power divider with arbitrary division ratio

For the first time, an out-of-phase power divider with arbitrary division ratio is proposed. The design equations of the proposed power divider are derived by using odd- and even-mode analysis. It can be found that the arm with higher characteristic impedance couples more power than the one with lower impedance. Because the power divider is fed by the parallel-strip line at the input port, the phase difference between the two output ports is 180° and frequency-independent in the equal dividing case. A small phase offset (180° ± Δ) over a broad bandwidth can be mainly attributed to the asymmetrical structure in the unequal dividing case. Therefore only impedance bandwidth needs to be considered in this design. To verify the proposed idea, an unequal (2:1) out-of-phase power divider is designed and measured, showing a broad bandwidth from 1.375 to 2.3°GHz (about 50°). The simulated and measured results are presented and show good agreement.