Compact cross-coupled circular cavity filters using multilayer substrate integrated waveguide

Using standard low-temperature co-fired ceramic technology, a novel fourth-order cross-coupled circular cavity filter is proposed, where multilayer substrate integrated waveguides are implemented. In particular, one slot is introduced on the metal surface of one filter, which can suppress the spurious mode in the filter cavities effectively. Good agreement is obtained between the simulated and measured S-parameters of the proposed new structure.