Optimized Design of Differential Moderate-Band BPF on Coupled Slotline Resonators

This letter presents an optimized design of differential moderate-band bandpass filter (BPF) with intrinsic common-mode rejection on three half-wavelength slotline resonators. The slotline resonator element's unloaded Q-factor is highly enhanced by using a long coupling length. Thus, it can be utilized to construct a low insertion loss differential moderate-band BPF.