Design of novel multiband bandpass filters based on coupled symmetric short-circuit stub multimode resonators

In this letter, the working mechanism of suggested bandpass filters with connected symmetric short-circuit stub multimode resonators is described. Because of the design flexibility, the suggested bandpass filters' centre frequencies may be modified based on the design approach. Meanwhile, the suggested bandpass filters have reduced insertion losses and compact sizes. A prototype is built and tested with six passbands centred at 1.57/2.38/3.55/5.14/5.83/6.78 GHz to confirm the design and analysis. Good agreement between the simulated, and measured results is observed, indicating that the proposed structure can be applied in the field of communication, information, and automation.