Completely Tuned Coupled Cavity Filters in Defected Bed of Nails Cavity
The design of perfectly tuned bandpass filters on defected bed of nails cavity and ridge gap waveguide (RGW) is investigated. The proposed technology eliminates the need for intact electrical contact between the metal parts of the filter. A space mapping method and coupling matrix are used to tune and optimize the proposed structures, which are computationally expensive and have beneficial characteristics for high-frequency applications. RGW is used as the input/output for the filters. A new coaxial transition to RGW and input/output coupling method is designed and used. A fifth-order Chebyshev bandpass filter is designed, fabricated, and measured. The performance of the designed filter is compared to a rectangular waveguide filter. Classic bandpass filters with transmission zeros at finite frequencies using this technology are designed for the first time. Sample models for triplet and quadruplet sections are proposed and optimized.