Reconfigurable quasi-elliptic filtering power divider with continuously tunable centre frequency and bandwidth

This study presents a new reconfigurable quasi-elliptic filtering power divider (FPD) with tunable centre frequency (CF) and bandwidth (BW) by exploring singly one varactor-loaded triple-mode resonator. Avoiding the need for the variable couplings of the inter-resonant nodes and external input/output, the reconfigurability of the proposed FPD is achieved by only tuning the resonant nodes of the triple-mode resonator. Compared to the other reported ones, the proposed FPD not only exhibits better performance, but also compact and concise topology with the reduced number of resonators and loaded varactors. For demonstration, a prototype of tunable FPD is implemented following the given design procedure. Measured results coincide well with simulated ones, exhibiting that tunable CF (1.5-1.91 GHz), 1-dB BW (80-300 MHz) with better in-band isolation (>18 dB).