Using coupled vias for band-pass filters in multilayered printed-circuit boards
This contribution extends previous work of the authors on microwave couplers using vias (plated through holes). In  a novel concept for microwave coupler design using vias in multilayered printed circuit boards (PCBs) was presented. By placing thru vias inside a ground via cage, high coupling between the vias can be observed. In this work it is shown that appropriate definition of via ports leads to a filter behavior of the structure. By adjusting the dimensions of the structure and by adding further thru vias the filter behavior can be controlled. Results are validated by physics-based and full-wave simulations up to 40 GHz.