Conductive Polymer Metallized Vias: A New Approach for Substrate Integrated Waveguide Development

Substrate integrated waveguides (SIWs) have huge potential for the development of microwave and millimeter-wave components in modern communication devices. Herein, a novel approach based on the vacuum suction of conductive polymer is introduced to substitute classical Cu electroplating technique for the simple and rapid metallization of conductive vias embedded in the dielectric substrate. Various combinations of vacuum level and vacuum duration are tested on vias with different geometries. Meaningfully, with the proper control of these two parameters, the specific partial height via becomes achievable in a single-layer substrate. As a proof of concept, two bandstop SIW filters based on the partial height via resonator are developed in a self-made flexible substrate and a commercial rigid laminate. Relatively good agreement can be seen between the measured and simulated results of their reflection coefficients and resonant frequencies, which confirm the reliability and robustness of this approach for the future SIW development.