A Zero Phase Delay Power Divider Using Zero Phase Impedance Transformer

The 3-dB power divider is one of the most common three-port device in microwave systems, which equally splits the signal at its two output ports. In previous Wilkinson power divider design, the phase delay between the input and output ports is not considered into the design requirements. However, the zero-phase shifting power divider attracts great interest in modern microwave systems. In this letter, a 3-dB power divider with zero-phase delay is designed based on a zero-phase impedance transformer. Instead of metamaterial transmission line, a transmission line stub is added to connect the isolation resistor, and a capacitor is insert between the output ports and the end of main branch to cancel out the imaginary part of even-odd mode impedances. With this new design, it releases the layout restriction that the two branches route around to connect to lumped element resistor. Closed-form design equations are derived and a prototype device is then simulated and measured. The measurement results agree well with the simulation results.