Improvement of manufacturing process for multilayer substrate integrated waveguide cavity

Substrate integrated waveguide (SIW) filters using low-temperature co-fired ceramic (LTCC) process exhibit the features of high-Q factor, miniature sizes, and high-power capability, which are attracting much attention recently. However, impropriate manufacturing process, i.e., dislocation, mismatch inner stresses, inner crack during the LTCC process, which will cause their frequency shift, degradation of quality factor, discrepancy of insertion loss and reliability. This paper analyzes mutual connection between the microwave characteristic and process parameters, exhibits the impact mechanism from LTCC process parameters to the stress, and proposes the method to improve the inner mismatching stress. Finally, by verifying improved methods and modifying the process models during the experiments of multilayer SIW filters, it can considerably improve their microwave performances, which can support the research and application of SIW components.