Low-temperature cofired ceramic (LTCC) ridge waveguide bandpass chip filters

Hull-wave mode-matching-based design of generalized ridge waveguide evanesc ent mode bandpass filters and their transitions for low-temperature cofired ceramic (LTCC) application is described, A modification factor is introduc ed in the prototype filter design to effectively overcome the filter bandwi dth distortion. Design examples are given to demonstrate the validity. An X -band single-ridge waveguide filter and its transitions are simulated and s uccessfully built in LTCC packages. Good agreement between the theory and e xperiment is obtained, which demonstrates the feasibility of the three-dime nsional ridge waveguide filter embedding in LTCC packages. As compared with an LTCC inductive windows waveguide filter realization, the ridge waveguid e filter realization shows significant advantages of smaller size and compa rable loss. Design consideration and LTCC realization of the low-loss ridge waveguide filter are also provided.