Compact power divider for wideband in-phase and out-of-phase performances using parallel coupled lines

摘要

A novel structure that can operate as an in-phase and out-of-phase power divider across 100% fractional bandwidth is presented. The proposed structure adopts two pairs of parallel-coupled lines to enable changing the operation from in-phase to out-of-phase while improving the return loss and isolation of a traditional Wilkinson power divider. Moreover, the device includes a stepped impedance T-junction for input port impedance matching. Changing the status of two terminals of one pair of coupled lines from open-ended to short-ended allows achieving changing the operation from in-phase to out-of-phase performance. Using a chip capacitor between the coupled lines enables realising the needed tight coupling without the need to have narrow gaps. A prototype is fabricated and measured. Simulated and measured results show more than 10 dB of return loss and more than 15 dB of isolation across the investigated band 1-3 GHz. In addition, the device provides <;1° phase imbalance and 0.2 dB amplitude imbalance in the in-phase and out-of-phase states across the whole frequency band.