Dual-band bandpass Wilkinson power divider of controllable bandwidths

In this reported work, quarter-wavelength stepped-impedance resonators with K inverters have been employed to realise a dual-band bandpass Wilkinson power divider (WPD). The individual bandwidth of each passband can be controlled with the dualband resonators and K inverters. A systematic design approach of the power divider is provided with the aid of the even-odd mode analysis and verified by circuit simulation. A 2.45/5.8 GHz WPD with a Chebyshev response has also been implemented for validation. The measured fractional bandwidth of 20 dB return loss (1/| S 11 |) is 7.0%/4.1% which is consistent with the theoretical design. In addition to the 3 dB power division, an insertion loss of 0.8/1.2 dB is obtained. Isolation of 20.1/19 dB at the centre frequency is also achieved. Full-wave simulated data are also presented and show good agreement with measured results. Compared with other dual-band bandpass power dividers, the proposed circuit exhibits better impedance matching and bandwidth.