Design of a Broadband Wilkinson Power Divider With Wide Range Tunable Bandwidths by Adding a Pair of Capacitors

In this brief, a novel two-way power divider with a wide range tunable bandwidth is presented and investigated. The proposed power divider is designed based on adding a pair of capacitors in parallel with the transmission lines in a Trantanella-type of Wilkinson power divider. The proposed power divider provides an additional zero-reflection frequency which will significantly increase the bandwidth compared with a conventional Wilkinson power divider. Moreover, the added zero-reflection frequency is sensitive to the capacitors so that the bandwidth can be tuned by altering the capacitance of the capacitors. Analytic design methods and formulas are derived and presented in detail. A two-way power divider is designed and measured to validate the proposed method. The measurement indicates that the device has a 15-dB bandwidth of ${ \boldsymbol {f}}_{ \boldsymbol {H}}/{ \boldsymbol {f}}_{ \boldsymbol {L}}\boldsymbol {=}\boldsymbol {2.73:1}$ (0.75–2.05 GHz). The proposed method can be applied for multi-way multi-section power dividers. Meanwhile, an eight-way power divider is designed and fabricated. The measured response has a bandwidth of ${ \boldsymbol {f}}_{ \boldsymbol {H}}\boldsymbol {/}{ \boldsymbol {f}}_{ \boldsymbol {L}}\boldsymbol {=}\boldsymbol {2.67:1}$ (0.75–2 GHz) with all the S-parameters better than −13 dB. The proposed power dividers have a wide bandwidth, compact size, good physical and electrical isolation feature. The measurement agrees well with the theoretical prediction which validates the proposed design theory.