Compact Tri-Band Bandpass Filter Using Novel Eight-Mode Resonator for 5G WiFi Application

This letter presents a novel compact tri-band bandpass filter (BPF) with wide third passband to satisfy the requirement of 5G WiFi. The proposed filter utilizes a novel multi-stub-loaded resonator with eight resonance modes. By utilizing these modes, a tri-band BPF with controllable operating frequencies is designed. Among the three bands, the highest one is formed by four modes to cover the 5G WiFi band. Each of the other two passbands centered at 2.4 and 3.5 GHz is realized by two modes. To validate the proposed idea, an experimental filter is implemented. Good agreement between the predicated and measured results demonstrates the proposed idea.