Balanced BPF with controllable dual passband performance

In this paper, balanced bandpass filter (BPF) with controllable dual passband performance is presented. Based on the voltage distribution of traditional half-wavelength resonator, the stub-loaded theory with independently controlled differential-mode resonances is presented and applied to design dual-band balanced BPF with independently controlled passband locations. Then, except for the main coupling path, by introducing coupling between the loaded stubs, another coupling path can be obtained to independently control the bandwidth of the first differential-mode passband. To validate the proposed idea, the balanced dual-band BPF is designed and simulated.