Compact Microwave Bandpass Filter using Multilayer Resonator-Embedded Packaging

The design of a compact microwave multilayer bandpass filter with aperture couplings and with an embedded-resonator topology is shown and investigated in this paper. Different types of inter-resonator and resonator-feedline couplings, in a three metallic-layer configuration, are presented. The bandpass filter is designed using coupling coefficients extracted through a full-wave electromagnetic-field simulation. The proposed multilayer configuration demonstrates a significant size reduction (about 50% in surface area), compared to a classical microstrip filter. The designed filters were realized in both classical electro-chemical and mechanical engraving technologies, in order to verify the influence of the manufacturing process on the filter characteristics. The measured parameters of the experimental models demonstrate the validity of the design method, based on electromagnetic-field simulation.