Monoblock Quintet-Section Dielectric Triple-Mode Resonator BPFs With Flexible Transmission Zeros

In this letter, novel monoblock dielectric waveguide filters (DWFs) with three flexibly allocable transmission zeros (TZs) are accurately designed by cascading a novel triple-mode dielectric waveguide resonator (DWR) and two TM<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">110</sub> DWRs based on a quintet-section scheme. Resonance behaviors of the triple-mode DWR are investigated, and individual controls of all the interresonance couplings are achieved. All three TZs can be precisely designed and realized by adjusting the proposed coupling structures. Two example DWFs with three TZs either above or below the passband are demonstrated, and one of which is further fabricated. The measured responses of the DWF show excellent agreement with the simulations and manifest the attractive features of the proposed DWF, such as compactness, low loss, and sharp frequency selectivity.