Quasi-Elliptic Lossy Filter With Reconfigurable Bandwidth

This letter proposed a quasi-elliptic lossy filter with a wide tunable bandwidth and enhanced passband flatness. For adapting the limited circuit sizes, a new type of lossy technique named center-loaded resistive-cross-couplings (CLRCCs) is proposed. By loading resistor coupling at the centers of half-wavelength resonators, additional mid-passband losses can be introduced to flatten the passband. A bandwidth reconfigurable five-pole filter with a hybrid structure is developed for the examination. The measured promising results showed the superiority of the proposed novel lossy method for wideband tunable filters.