Design of miniaturized bandpass filters using quasi-lumped Multilayer Resonators

A novel design procedure for a compact multilayer bandpass filter is proposed and examined. The filter is realized using quasi-lumped multilayer resonators. Based on the orientation of these coupled-resonator pairs, a second-order bandpass filter is realized with transmission zeros. In order to achieve a low external quality factor, i.e., a wider filter bandwidth, different types of feeder realization are considered. The design methodology with all relevant steps is presented and the equivalent-circuit of the resonator is also derived and verified. The filter design is simulated using a 3D electromagnetic model and validated by measurements on the fabricated filter. The simulation and experimental results are in good agreement.