Photoimageable thick-film technology-Benefits
of choosing this structure-pcb
Benefits of choosing this structure
Edge coupled band-pass filters were chosen for this study as they are one of the most common and useful microwave and millimetre-wave planar components. The filter performance is based on the coupling between the resonant sections and controlled by the size of the gap.This characteristic makes edge coupled band-pass filters very sensitive to fabrication errors.
Another reason of choosing this structure in a multi-layer form is due to limitation on the structure when it has been fabricated on a single layer. The gap between the two resonant structures becomes very small and cannot easily be fabricated due to the limitations of low-cost fabrication technologies. In multi-layer circuits, the coupling between resonant sections is achieved by overlapping conductors which are separated by a thin dielectric layer. However, to some extent the problem of fabricating small gaps has been exchanged for that of achieving high alignment between the conductor layers. Normally a modern mask aligner will be needed to achieve the required degree of resolution.