SIW Q-band filters using advanced multilayer PCB technology

This paper deals with the design of Q-band filters using a low-cost multilayered Printed Circuit Board (PCB) substrate. In order to meet strong electrical specifications, the Substrate Integrated Waveguide (SIW) technique has been used to take profit of the complete build-up of the multilayered PCB. Advanced fabrication techniques of vias and micro-vias have also been developed in this project to implement 4th and 6th-order filters in this technology. The challenge here is to use a standard PCB process to design complex microwave devices that usually require accurate fabrication process and very low tolerances, especially in such frequency ranges. Based on that, two 2.8×8mm2 prototypes have been designed, simulated and fabricated on a 1mm-thick PCB made of copper and blend of high performance resin material. Regarding the results of these filters, measured insertion & return losses are in a very good agreement with the simulation while exhibiting high rejections and low footprint.